Convert any number of seconds into decimal minutes, MM:SS and HH:MM:SS, and turn minutes back into seconds.
Enter a number of seconds. You get minutes as a decimal, the clock-style MM:SS breakdown and every larger unit.
In minutes
1.50
90 seconds is 1 minute and 30 seconds
Enter minutes, with an optional extra seconds box for values like 4 minutes 20 seconds.
In seconds
260
4 minutes and 20 seconds is 260 seconds
To convert seconds to minutes, divide the seconds by 60. So 300 seconds is exactly 5 minutes, 3,600 seconds is 60 minutes, and 86,400 seconds is 1,440 minutes, which is a full day. The answer often arrives as a decimal: 90 seconds divided by 60 is 1.5 minutes. A clock, a stopwatch and a media player will not display 1.5. They display 1:30, because the digits after the colon are seconds, not hundredths, and half a minute is 30 seconds. Both readings describe the same 90 seconds.
minutes = seconds ÷ 60 90 ÷ 60 = 1.5 minutes → 1:30 (1 min 30 s) 300 ÷ 60 = 5 minutes → 5:00 (5 min flat) 3,600 ÷ 60 = 60 minutes → 1:00:00 (1 hour)The second is the base unit of time, and almost everything else is built on top of it. A minute is 60 of them, an hour is 3,600, a day is 86,400 and a week is 604,800. Because the second sits at the bottom of that stack, it is the unit machines prefer: cache headers, rate limits, timestamps, video durations, timers and race clocks all count in whole seconds. Humans, on the other hand, think in minutes. This converter sits between the two.
The tool at the top of this page has two tabs, and each one answers a different half of the question:
Everything runs in your browser. Nothing is uploaded, nothing is stored, and the page keeps working with the connection off. If you need to add several durations together before converting, use the Time Calculator first and bring the total here. If your number is already in minutes and you want hours, the Minutes to Hours converter is the shorter path, and if the destination is a payroll or invoicing field, the Decimal Hours Converter produces the format those systems expect.
The rest of this page is the reference material: a large seconds chart covering every value people search for, the cache and timeout durations that software expresses in seconds, the reverse table for minutes to seconds, the real definition of a second, and a plain explanation of why 90 seconds is both 1.5 minutes and 1:30 without either being wrong.
Four steps, about ten seconds of work. The result updates as you type, so you can leave the page open while you feed numbers into it.
Use Seconds to Minutes when you have a raw second count from a log file, a timer or a stopwatch. Use Minutes to Seconds when a settings field wants whole seconds.
Type the seconds, or tap a preset for 60, 90, 300, 3600 or 86400. Decimals are accepted, so 12.5 seconds works. In the reverse tab, add loose seconds in the second box.
Decimal minutes for arithmetic, MM:SS for a timer or a media player, HH:MM:SS once the value passes an hour, and hours, days or weeks for anything longer.
Open Show the working to see the division, the whole minutes and the leftover seconds written out, so you can verify the answer rather than trust it.
Copy the right field. The decimal minutes box and the MM:SS box hold the same duration in different clothes. Pasting 1.5 into a field that expects MM:SS produces one minute and five seconds in some players, and pasting 1:30 into a spreadsheet cell formatted as a number produces something else again. Decide which format the destination wants before you copy.
One division and one remainder. Everything else on this page is a consequence of those two operations.
A minute is defined as exactly 60 seconds, so the conversion is a single division with no approximation anywhere in it.
decimal minutes = seconds ÷ 60
That gives 300 ÷ 60 = 5, and 90 ÷ 60 = 1.5. Some values do not land on a tidy decimal: 100 seconds is 1.6666 recurring minutes, which is why the clock form is usually the more honest way to write it.
For a clock display you want two integers instead of one decimal. Integer division gives the whole minutes and the remainder gives the seconds left over.
whole minutes = floor(seconds ÷ 60) leftover seconds = seconds mod 60
For 100 seconds that is floor(100 ÷ 60) = 1 and 100 mod 60 = 40, so 1:40. The remainder is always between 0 and 59, which is exactly what the two digits after the colon are allowed to hold.
Once the minute count passes 59 you can peel an hour off the front. This is optional: 90 minutes and 1:30:00 are equally correct, they just suit different readers.
hours = floor(seconds ÷ 3600) minutes = floor((seconds mod 3600) ÷ 60) seconds = seconds mod 60
So 5,400 seconds is 90 minutes, or 1:30:00, or 1.5 hours. A stopwatch would show 90:00, a video editor would show 1:30:00, and a timesheet would want 1.5.
This single point causes more confusion than the rest of the conversion put together, so it is worth stating slowly. Ninety seconds is one full minute with 30 seconds left over. Thirty seconds is half of sixty, so the leftover is half a minute, and half written as a decimal is 0.5. The decimal reading is therefore 1.5 minutes. The clock reading writes the leftover in its own unit instead of as a fraction, so it prints 1:30, meaning one minute and thirty seconds.
90 s = 1 minute + 30 seconds = 1 + (30 ÷ 60) minutes = 1.5 minutes → displayed as 1:30 1.30 minutes = 1 minute + (0.30 × 60) seconds = 1 min 18 s = 78 s
The trap is that 1.30 and 1:30 differ by a single character and look almost identical in a printed list, yet they are 12 seconds apart. The same mismatch appears one level up with hours, where writing 7 hours 30 minutes as 7.30 instead of 7.50 quietly deletes 12 minutes of pay. The rule is identical in both places: a fraction of a unit is not the same as a count of the unit below it, and you convert between them by multiplying or dividing by 60.
MM:SS can exceed 60 minutes. A duration is not a clock reading, so there is no rule that stops the minutes column at 59. A long podcast episode legitimately shows 92:14 in some players and 1:32:14 in others. Both are 5,534 seconds. Only a time of day has to keep its fields in range.
The same number of seconds can be written five or six ways. Picking the wrong one for the destination is the most common cause of a duration going astray.
| Format | 3,725 s looks like | Best for | Where it goes wrong |
|---|---|---|---|
| Whole seconds | 3725 | Config files, APIs, databases, logs, cache headers. | Unreadable to humans past about two minutes. |
| Decimal minutes | 62.083 | Averaging, multiplying, charting, spreadsheets. | Recurring decimals: 100 s is 1.6666 minutes forever. |
| MM:SS | 62:05 | Stopwatches, timers, music players, race splits. | Mistaken for minutes and hundredths by spreadsheets. |
| HH:MM:SS | 1:02:05 | Video runtimes, long recordings, shift durations. | Leading zeros vary: 01:02:05 and 1:02:05 both appear. |
| Decimal hours | 1.035 | Payroll, invoicing, anything multiplied by a rate. | Loses precision fast if you round to two places. |
| ISO 8601 duration | PT1H2M5S | APIs, calendar files, structured data on web pages. | Not human readable and easy to mistype. |
| Timecode HH:MM:SS:FF | 01:02:05:00 | Film and video editing, broadcast delivery. | The last field is frames, not hundredths of a second. |
Decimal hours for 3,725 seconds is 3,725 ÷ 3,600 = 1.0347, shown here rounded to three places. If that is the column you need, the Decimal Hours Converter handles the rounding rules that payroll systems apply.
Anything a person watches tick should be MM:SS. Nobody counts down from 4.75 minutes. They count down from 4:45, because the second digit pair is the thing actually changing.
Averages, totals and rates need a single number. Five lap times of 92, 89, 95, 88 and 91 seconds average to 91 seconds, which is 1.517 minutes, or 1:31 on the clock.
Machines want integers. A cache header, a timeout, a retry delay and a token lifetime are all plain second counts, with no colon and no unit suffix.
Every value people actually look up, from a single second to a full day. Exact figures, with hours rounded to six decimal places only where the division recurs.
| Seconds | Decimal minutes | MM:SS | HH:MM:SS | Hours |
|---|---|---|---|---|
| 1 | 0.016667 | 0:01 | 0:00:01 | 0.000278 |
| 5 | 0.083333 | 0:05 | 0:00:05 | 0.001389 |
| 10 | 0.166667 | 0:10 | 0:00:10 | 0.002778 |
| 15 | 0.25 | 0:15 | 0:00:15 | 0.004167 |
| 30 | 0.5 | 0:30 | 0:00:30 | 0.008333 |
| 45 | 0.75 | 0:45 | 0:00:45 | 0.0125 |
| 60 | 1 | 1:00 | 0:01:00 | 0.016667 |
| 90 | 1.5 | 1:30 | 0:01:30 | 0.025 |
| 100 | 1.666667 | 1:40 | 0:01:40 | 0.027778 |
| 120 | 2 | 2:00 | 0:02:00 | 0.033333 |
| 150 | 2.5 | 2:30 | 0:02:30 | 0.041667 |
| 180 | 3 | 3:00 | 0:03:00 | 0.05 |
| 240 | 4 | 4:00 | 0:04:00 | 0.066667 |
| 300 | 5 | 5:00 | 0:05:00 | 0.083333 |
| 360 | 6 | 6:00 | 0:06:00 | 0.1 |
| 420 | 7 | 7:00 | 0:07:00 | 0.116667 |
| 480 | 8 | 8:00 | 0:08:00 | 0.133333 |
| 600 | 10 | 10:00 | 0:10:00 | 0.166667 |
| 900 | 15 | 15:00 | 0:15:00 | 0.25 |
| 1,200 | 20 | 20:00 | 0:20:00 | 0.333333 |
| 1,800 | 30 | 30:00 | 0:30:00 | 0.5 |
| 2,700 | 45 | 45:00 | 0:45:00 | 0.75 |
| 3,600 | 60 | 60:00 | 1:00:00 | 1 |
| 5,400 | 90 | 90:00 | 1:30:00 | 1.5 |
| 7,200 | 120 | 120:00 | 2:00:00 | 2 |
| 10,800 | 180 | 180:00 | 3:00:00 | 3 |
| 21,600 | 360 | 360:00 | 6:00:00 | 6 |
| 43,200 | 720 | 720:00 | 12:00:00 | 12 |
| 86,400 | 1,440 | 1440:00 | 24:00:00 | 24 |
Bold rows are the anchors worth memorising: 60 seconds is a minute, 90 is a minute and a half, 300 is five minutes, 3,600 is an hour and 86,400 is a day. Every other row is one of those scaled. For durations longer than a day, keep going: 604,800 seconds is a week, and 2,592,000 seconds is 30 days.
Software almost never asks for a duration in minutes. Cache headers, session lifetimes, retry delays and DNS records are written as a plain number of seconds, which is why a value like 2592000 shows up in configuration files with no explanation attached. This table decodes the ones you will meet most often.
| Seconds | Minutes | Hours | Human label | Typically used for |
|---|---|---|---|---|
| 60 | 1 | 0.016667 | 1 minute | Short-lived API responses, health checks, rate limit windows. |
| 300 | 5 | 0.083333 | 5 minutes | The default TTL in countless caches and DNS records. |
| 900 | 15 | 0.25 | 15 minutes | Access token lifetimes, idle session timeouts. |
| 3,600 | 60 | 1 | 1 hour | Standard max-age for pages that change during the day. |
| 86,400 | 1,440 | 24 | 1 day | Daily caches, cookie lifetimes, DNS records that rarely move. |
| 604,800 | 10,080 | 168 | 7 days (1 week) | Refresh tokens, weekly digests, medium-lived assets. |
| 2,592,000 | 43,200 | 720 | 30 days | Long-lived cookies, monthly billing windows, static assets. |
| 31,536,000 | 525,600 | 8,760 | 365 days | Fingerprinted assets and long security policy lifetimes. |
Note the arithmetic on the last two rows: 30 days is 30 × 86,400 = 2,592,000 seconds, and 365 days is 365 × 86,400 = 31,536,000 seconds. Neither accounts for leap years or daylight saving shifts, because these are counts of elapsed seconds rather than calendar dates. When the calendar matters, use the Date Calculator instead.
Going back down the ladder is a multiplication instead of a division, and it never produces a recurring decimal.
Multiply the minutes by 60, then add any loose seconds.
seconds = (minutes × 60) + extra seconds 4 min 20 s = (4 × 60) + 20 = 260 seconds 12.5 min = 12.5 × 60 = 750 seconds 90 min = 90 × 60 = 5,400 seconds| Minutes | Seconds | HH:MM:SS | Hours |
|---|---|---|---|
| 1 | 60 | 0:01:00 | 0.016667 |
| 2 | 120 | 0:02:00 | 0.033333 |
| 3 | 180 | 0:03:00 | 0.05 |
| 4 | 240 | 0:04:00 | 0.066667 |
| 5 | 300 | 0:05:00 | 0.083333 |
| 10 | 600 | 0:10:00 | 0.166667 |
| 15 | 900 | 0:15:00 | 0.25 |
| 20 | 1,200 | 0:20:00 | 0.333333 |
| 25 | 1,500 | 0:25:00 | 0.416667 |
| 30 | 1,800 | 0:30:00 | 0.5 |
| 40 | 2,400 | 0:40:00 | 0.666667 |
| 45 | 2,700 | 0:45:00 | 0.75 |
| 50 | 3,000 | 0:50:00 | 0.833333 |
| 60 | 3,600 | 1:00:00 | 1 |
| 75 | 4,500 | 1:15:00 | 1.25 |
| 90 | 5,400 | 1:30:00 | 1.5 |
| 100 | 6,000 | 1:40:00 | 1.666667 |
| 120 | 7,200 | 2:00:00 | 2 |
| 150 | 9,000 | 2:30:00 | 2.5 |
| 180 | 10,800 | 3:00:00 | 3 |
| 240 | 14,400 | 4:00:00 | 4 |
| 480 | 28,800 | 8:00:00 | 8 |
| 720 | 43,200 | 12:00:00 | 12 |
| 1,440 | 86,400 | 24:00:00 | 24 |
Notice that 90 minutes appears here as 5,400 seconds while 90 seconds appears in the previous table as 1.5 minutes. The number 90 turns up at both scales, which is a small but reliable source of mix-ups when you are reading a column of figures quickly. If the numbers you are converting are shift lengths rather than durations, the Hours Calculator keeps the labels attached for you.
Multiplying works just as cleanly on decimals. A quarter of a minute is 0.25 × 60 = 15 seconds. A third of a minute is 20 seconds, and two thirds is 40 seconds, which is why 1.6666 recurring minutes is exactly 100 seconds with nothing lost. The recurring decimal is an artefact of writing thirds in base 10, not a real imprecision in the duration.
0.10 min = 6 s 0.25 min = 15 s 0.33 min = 20 s (recurring) 0.50 min = 30 s 0.75 min = 45 s 0.90 min = 54 s
Two diagrams that cover most of what there is to know: how each unit nests inside the next, and how seconds map onto the decimal fraction of a minute.
Computers store durations as integers because integers cannot be ambiguous. The second is the natural integer unit, so it is what nearly every configuration field expects.
An HTTP response can carry Cache-Control: max-age=3600, which tells the browser that the file stays fresh for 3,600 seconds, or one hour, before it needs checking again. There is no unit in the header, only the number, so a mistyped extra zero turns an hour into ten hours and a missing one turns it into six minutes. The same convention runs through DNS records, where a TTL of 300 means the record may be cached for five minutes, and through content delivery networks, where 2,592,000 is the familiar thirty-day setting for files that never change.
A rate limit is a count paired with a window in seconds: 100 requests per 60 seconds, or 5,000 per 3,600 seconds. When you exceed it, a well behaved API replies with a Retry-After header, again in seconds. If it says 900 you are waiting a quarter of an hour, which is a much clearer thing to read once you have converted it. Exponential backoff schedules are built the same way, doubling a delay in seconds until it reaches a ceiling.
A Unix timestamp is the number of seconds elapsed since 00:00:00 UTC on 1 January 1970. It is a single integer, so subtracting two of them gives an exact duration in seconds with no calendar arithmetic and no time zone confusion. The timestamp 1,000,000,000 fell on 9 September 2001 at 01:46:40 UTC, and 1,700,000,000 fell on 14 November 2023 at 22:13:20 UTC. Because the count is in seconds, converting a timestamp difference into something readable is exactly the division this page is about.
Milliseconds hide in plain sight. JavaScript's Date.now() returns milliseconds, not seconds, while most server APIs and JWT claims use seconds. Feeding one into the other is a factor of 1,000 error, which turns a token that expires in an hour into one that expires in 3.6 seconds. Check the unit before you compare two numbers that both look like timestamps.
A signed 32-bit integer can hold at most 2,147,483,647 seconds. Counting that many seconds from the 1970 epoch lands on 19 January 2038 at 03:14:07 UTC, after which the counter overflows to a negative number and the date reads as 1901. That is roughly 68 years of seconds in a single 32-bit field. Modern systems use 64-bit timestamps, which push the limit far beyond any practical horizon, but embedded devices and old file formats still carry the smaller field.
Short-lived access tokens commonly last 900 or 3,600 seconds, refresh tokens 604,800 or 2,592,000. Cookies carry both a Max-Age in seconds and an absolute expiry date, and when the two disagree the seconds value wins in most browsers. Reading these as minutes and days rather than raw integers makes it far easier to notice when one of them is wrong by an order of magnitude.
Video, audio, sport, cooking and training all count in seconds and display in MM:SS. Each field has its own habits worth knowing.
Platforms report duration in seconds and display it as MM:SS or HH:MM:SS. A 90-second clip is 1:30, a 15-minute upload is 900 seconds, and a two-hour feature is 7,200 seconds. Advertising is bought in fixed second lengths: 6, 15, 30 and 60.
Editors work in HH:MM:SS:FF, where the last pair counts frames inside the current second, not hundredths. At 25 frames per second the position 00:01:30:12 is 90.48 seconds. Reading frames as decimals is a classic beginner error.
Splits are recorded in seconds and hundredths, then totalled and averaged in seconds before being converted back. Four laps of 92, 89, 95 and 88 seconds total 364 seconds, which is 6:04, and average 91 seconds, which is 1:31.
Recipes mix units freely: 90 seconds in the microwave, 3 minutes for soft noodles, 360 seconds for a six-minute egg. Timers accept MM:SS, so 2:30 is two and a half minutes and never two minutes thirty hundredths.
Intervals are pure second arithmetic. Eight rounds of 20 seconds work and 10 seconds rest is 8 × 30 = 240 seconds, exactly 4 minutes. Twelve rounds of 40 on and 20 off is 12 × 60 = 720 seconds, or 12 minutes.
Digital audio is measured per second: 44,100 samples per second on a CD, 48,000 in video production. A three-minute song is 180 seconds, which at 44,100 samples per second is 7,938,000 samples per channel.
Broadcast video in North America runs at 29.97 frames per second rather than a round 30, a legacy of the switch to colour television. Counting 30 frames per second against material that actually delivers 29.97 makes the timecode drift ahead of real elapsed time by about 3.6 seconds per hour, which is 108 frames. Drop-frame timecode fixes this by skipping two frame numbers at the start of every minute except every tenth minute, which removes exactly 108 numbers per hour and keeps the display honest. No frames are lost; only labels are skipped. If you are adding up clip durations rather than reading positions, convert to seconds first and the whole issue disappears.
Counting down rather than converting? If what you actually want is a live timer that ticks from a duration to zero, the Countdown Timer takes minutes and seconds directly. Use this page when you need the number, and that one when you need the ticking.
The minute and the hour are defined in terms of the second. The second is defined in terms of an atom, and has been since 1967.
The second is one of the seven base units of the International System of Units. Its definition fixes the frequency of a specific transition in the caesium-133 atom: the unperturbed ground-state hyperfine transition frequency is defined to be exactly 9,192,631,770 hertz. Since a hertz is one cycle per second, that sentence turns around neatly. One second is the time taken for 9,192,631,770 cycles of that radiation.
The point of the definition is reproducibility. Any properly built caesium clock, anywhere, counts the same thing and agrees with every other one. Before 1967 the second was defined astronomically, first as a fraction of a mean solar day and later as a fraction of a particular tropical year, both of which depend on the Earth, which is not a perfectly steady timekeeper.
1 second = 9,192,631,770 cycles of caesium-133 hyperfine radiation 1 minute = 60 seconds (exact, by definition) 1 hour = 3,600 seconds (exact, by definition)
Atomic time is steady, but the Earth's rotation is not quite. Coordinated Universal Time, or UTC, keeps atomic seconds while occasionally inserting an extra second so that clock time stays within 0.9 seconds of the Earth's actual orientation. That extra second appears as 23:59:60, making one minute 61 seconds long. Twenty-seven leap seconds have been inserted since the system began in 1972, the most recent at the end of 31 December 2016.
Leap seconds cause real trouble for software that assumes every minute has exactly 60 seconds and every day exactly 86,400. In 2022 the General Conference on Weights and Measures resolved to stop inserting leap seconds by 2035, allowing the gap between UTC and the Earth's rotation to grow to a larger tolerance before any correction is applied. Until then, the practical advice is unchanged: assume 86,400 seconds in a day for ordinary arithmetic, and rely on a proper time library when a single second genuinely matters.
| Unit | Symbol | In seconds | Where it turns up |
|---|---|---|---|
| Millisecond | ms | 0.001 (10−3) | Network latency, screen refresh, reaction times. A 60 fps frame lasts 16.67 ms. |
| Microsecond | µs | 0.000001 (10−6) | Memory access, high frequency trading, audio buffer timing. |
| Nanosecond | ns | 0.000000001 (10−9) | Processor clock cycles. Light travels about 30 cm in one nanosecond. |
| Picosecond | ps | 10−12 | Transistor switching, laser pulses, signal timing inside chips. |
| Femtosecond | fs | 10−15 | Chemical bond vibration, ultrafast laser physics. |
Each step down is a factor of 1,000, which is why converting between them is a matter of moving the decimal point three places rather than dividing by 60. Only at the second does the system switch from powers of ten to the base-60 counting inherited from Babylonian astronomy, and that switch is the reason a minutes conversion needs a chart at all.
Sixty divides evenly by 2, 3, 4, 5, 6, 10, 12, 15, 20 and 30, which makes halves, thirds and quarters land on whole numbers. A hundred does not divide by 3, so a third of a decimal minute would recur forever. Attempts at decimal time have been made, most famously in revolutionary France in the 1790s with a ten-hour day, and none of them displaced a system that was already thousands of years old and worked well for splitting a duration into thirds.
Each one is solvable in the calculator above. The working is shown so you can check your own method against it.
A recipe says to simmer for 300 seconds and the kitchen timer wants minutes.
= 5 minutes exactly (5:00)
An export reports the runtime as 90 seconds and the delivery sheet wants minutes.
= 1.5 minutes, displayed 1:30
A response header reads Cache-Control: max-age=86400. How long is the file cached?
= 1,440 minutes = 24 hours = 1 day
Splits of 1:32, 1:29, 1:35, 1:28 and 1:31. What is the total and the average?
Total 7:35 · Average 1:31 per lap
Ten rounds of 45 seconds work and 15 seconds rest, after a 300 second warm up.
= 900 seconds = 15:00
A settings field wants a timeout in whole seconds and the policy says 30 minutes, with an extra 30 seconds of grace.
= 1,830 seconds (30.5 minutes)
Anyone whose tools count in seconds while their colleagues talk in minutes.
Reading TTLs, timeouts, retry delays and token lifetimes out of configuration files, and writing human durations back into them as integers.
Turning exported second counts into runtimes, checking a cut against a target length, and adding clip durations before converting the total.
Summing splits, averaging laps, planning interval sessions, and converting a session total from seconds into something a training log can hold.
Reporting response and resolution times that arrive from a ticketing system in seconds, then presenting them as minutes and hours.
Converting between the seconds a microwave counts and the minutes a recipe describes, then working backwards to a serving time.
Elapsed-time exercises, science experiments timed with a stopwatch, and checking homework answers on unit conversion problems.
Session lengths, dwell times and durations that log files record in seconds and reports have to present in readable units.
Average handle time, hold time and queue wait all arrive in seconds and get reported in minutes against a service target.
A phone stopwatch reports MM:SS.hh, and the hundredths after the second decimal are not seconds, which trips people up constantly.
If your durations are shifts rather than clips, two other tools are usually a better fit: the Time Duration Calculator for the gap between two clock times, and the Hours Calculator for adding a week of them together.
Almost every wrong answer in this area comes from one of these six.
| Mistake | What it looks like | The fix |
|---|---|---|
| Reading a colon as a decimal point | 1:30 treated as 1.30 | 1:30 is 1.5 minutes. Reading it as 1.30 loses 12 seconds on every value. |
| Dividing by 100 | 300 ÷ 100 = 3 minutes | Divide by 60. 300 seconds is 5 minutes. The base is 60, not 10. |
| Confusing seconds and milliseconds | 3600000 read as 3,600 s | 3,600,000 milliseconds is 3,600 seconds. Divide by 1,000 first, then by 60. |
| Rounding the remainder up to 60 | 119 s shown as 1:60 | The seconds field only holds 0 to 59. 119 seconds is 1:59, and 120 is 2:00. |
| Rounding decimal minutes too early | 100 s stored as 1.67 min | Keep three or more places through the working. Twenty entries of 1.67 instead of 1.6667 drift by four seconds. |
| Assuming a day is always 86,400 s | DST and leap second days | Clock change days run 82,800 or 90,000 seconds, and a leap second day runs 86,401. Use real timestamps when it matters. |
The daylight saving figures come straight from the arithmetic: a 23-hour day is 23 × 3,600 = 82,800 seconds and a 25-hour day is 25 × 3,600 = 90,000 seconds. Spans that cross one of those days are safest measured with the Time Duration Calculator, which compares two real moments rather than assuming a fixed day length.
The vocabulary that turns up around durations, timers and timestamps.
Direct answers to the questions people ask most about this calculation.
300 seconds is exactly 5 minutes, because 300 divided by 60 is 5 with no remainder. On a timer it shows as 5:00, and in HH:MM:SS form it is 0:05:00. It is a quarter of 1,200 seconds and a twelfth of an hour, which is why 300 turns up so often as a default cache or timeout value in software.
Divide the number of seconds by 60. If you want a clock-style answer instead of a decimal, take the whole number of minutes from the division and use the remainder as the seconds. For example 200 seconds divided by 60 is 3.333 minutes, and 200 minus 180 leaves 20 seconds, so the display form is 3:20.
Both readings describe the same duration. 90 seconds is one minute plus 30 seconds left over, and 30 seconds is half a minute, so the decimal is 1.5. The clock writes the leftover in seconds rather than as a fraction, giving 1:30. Writing 1.30 instead would mean 0.30 of a minute, which is 18 seconds, so 78 seconds in total.
3,600 seconds is 60 minutes, which is exactly one hour. The arithmetic is 60 seconds per minute multiplied by 60 minutes per hour. This is why the number 3,600 appears everywhere in configuration files: a cache header reading max-age=3600 is telling the browser to keep a file for one hour.
86,400 seconds is 1,440 minutes, which is 24 hours, or one full day. The chain is 86,400 divided by 60 equals 1,440 minutes, and 1,440 divided by 60 equals 24 hours. Days on which daylight saving time starts or ends are the exception, running 82,800 or 90,000 seconds instead.
There are exactly 60 seconds in a minute, by definition rather than by measurement. The only exception is a leap second, which makes one rare minute 61 seconds long by inserting 23:59:60 into UTC. Twenty-seven such seconds have been added since 1972, and the practice is scheduled to end by 2035.
Multiply the minutes by 60, then add any loose seconds. So 4 minutes 20 seconds is (4 times 60) plus 20, which is 260 seconds. Decimals work the same way: 12.5 minutes is 12.5 times 60, which is 750 seconds. The Minutes to Seconds tab on this page does both parts at once.
604,800 seconds is exactly one week. The working is 60 seconds times 60 minutes times 24 hours times 7 days. In other units it is 10,080 minutes or 168 hours. It appears frequently as a refresh token lifetime or a cache setting, where it means the item stays valid for seven days.
100 seconds is 1.667 minutes as a decimal, or 1:40 on a clock. The division gives 1 whole minute with 40 seconds left over, and 40 divided by 60 is 0.6666 recurring. The recurring decimal is just an artefact of base 10; the duration itself is exactly 100 seconds.
It means the response stays fresh for 3,600 seconds, which is one hour, before a browser or cache should check for a newer copy. The number is always a plain count of seconds with no unit attached, so 300 is five minutes, 86400 is a day and 2592000 is thirty days.
A leap second is an extra second inserted into UTC to keep clock time within 0.9 seconds of the Earth's rotation, displayed as 23:59:60. Twenty-seven have been added since 1972, the last at the end of 31 December 2016. In 2022 the General Conference on Weights and Measures agreed to discontinue them by 2035.
By atomic physics. The definition fixes the ground-state hyperfine transition frequency of caesium-133 at exactly 9,192,631,770 hertz, so one second is the time taken for that many cycles of the radiation. This has been the official definition since 1967. Before that the second was defined as a fraction of a day or of a year.
1.5 minutes is 90 seconds, because 1.5 multiplied by 60 is 90. The same span is written 1:30 on a timer. The pattern holds for any fraction: 0.25 minutes is 15 seconds, 0.5 is 30 seconds, 0.75 is 45 seconds and 2.5 minutes is 150 seconds.
Divide by 3,600, because an hour is 60 times 60 seconds. So 7,200 seconds is 2 hours, 5,400 seconds is 1.5 hours and 1,800 seconds is 0.5 hours. If you already have the value in minutes, dividing that by 60 gives the same answer, which is what the Minutes to Hours converter does.