Date & Time
Time Calculator
Add and subtract durations, or work out the hours between two clock times — including shifts that run past midnight.
Time Calculator
About the Time Calculator
Two jobs in one tool. Duration mode adds and subtracts spans of time — 2h 45m plus 1h 50m, or 8 hours minus 35 minutes. Between mode takes two clock times and returns the hours and minutes separating them, including shifts that run past midnight.
Every result comes with its decimal hours equivalent, which is the figure payroll and timesheet systems actually want. Two hours and thirty minutes is 2.5 decimal hours, not 2.30 — a conversion that costs people money surprisingly often.
The tool works with durations and clock times only. It does not convert between time zones, so both times are assumed to be in the same one.
How to use the Time Calculator
- Choose whether to add, subtract, or measure between two times.
- Enter the hours, minutes and seconds, or the two clock times.
- For shift work, add an unpaid break to deduct it.
- Select Calculate.
- An end time earlier than the start is treated as running past midnight.
Time addition calculator: adding hours and minutes
Time runs in base 60, not base 10, so ordinary decimal addition gives wrong answers. Convert everything to a single unit — seconds or minutes — add, then convert back.
1. Convert each time to total seconds: (h × 3600) + (m × 60) + s
2. Add or subtract those totals
3. Convert back: hours = total ÷ 3600, remainder ÷ 60 for minutes
Worked example
Add 2h 45m to 1h 50m.
2h 45m = 9,900 seconds. 1h 50m = 6,600 seconds.
Total: 16,500 seconds. Divided by 3,600 gives 4, with 2,100 seconds left over — that is 35 minutes.
4 hours 35 minutes — 4.583 decimal hours
Adding 2.45 and 1.50 as decimals would give 3.95, which is wrong twice over: wrong value, wrong meaning.
Decimal hours, and why they matter
Payroll systems work in decimal hours because they multiply directly by an hourly rate. Minutes must be converted by dividing by 60 — not by moving a decimal point.
| Minutes | Decimal hours | Minutes | Decimal hours |
|---|---|---|---|
| 5 | 0.083 | 35 | 0.583 |
| 10 | 0.167 | 40 | 0.667 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.333 | 50 | 0.833 |
| 25 | 0.417 | 55 | 0.917 |
| 30 | 0.5 | 60 | 1.0 |
The classic error is writing 7 hours 30 minutes as 7.30 instead of 7.5. At £15 an hour that is £3 lost on a single shift — and around £780 across a working year if it happens every day.
Working out a night shift
When a shift crosses midnight, the end time reads lower than the start and simple subtraction returns a negative. Add 24 hours to the end time before subtracting.
If end < start: hours = (end + 24:00) − start
A shift from 22:00 to 06:30 subtracts to −15.5 hours, which is meaningless. Add 24 to the end — 30:30 minus 22:00 — and you get 8 hours 30 minutes. This calculator handles it automatically in "between" mode.
| Start | End | Hours | Decimal |
|---|---|---|---|
| 22:00 | 06:00 | 8h 00m | 8.0 |
| 22:00 | 06:30 | 8h 30m | 8.5 |
| 23:15 | 07:45 | 8h 30m | 8.5 |
| 19:00 | 03:30 | 8h 30m | 8.5 |
| 09:00 | 17:30 | 8h 30m | 8.5 |
Remember to subtract unpaid breaks. An 8h 30m shift with a 30-minute unpaid lunch is 8 paid hours — run the subtraction in duration mode.
Overtime and time-and-a-half
Once you have decimal hours, overtime is straightforward. Time and a half multiplies the rate by 1.5; double time by 2.
Overtime pay = overtime hours × base rate × multiplier
Six overtime hours at £15 with time and a half: 6 × 15 × 1.5 = £135. Convert any part-hours to decimal first — 6h 20m is 6.333 hours, not 6.20.
Overtime rules are set by law and by contract, and they vary widely. In the US, federal law generally requires time and a half beyond 40 hours a week for non-exempt employees; other countries and contracts differ. Check what applies to you rather than assuming a multiplier.
What this tool does not do
It performs no time zone conversion. Both times are treated as being in the same zone, so it will not tell you what 3pm in London is in New York. It also has no daylight-saving awareness — on the two days a year when clocks change, a shift crossing the change is an hour longer or shorter than the arithmetic suggests.
For dates rather than clock times, use the date difference calculator. To work out an arrival from a distance and speed, try the arrival time calculator.
Time duration calculator: time between two times
Choose Time between two clock times. Enter the start and end times. The calculator gives the elapsed time in hours and minutes, and in decimal hours for payroll.
Worked example
A shift runs from 9:15 to 17:40 with a 30-minute unpaid break.
9:15 to 17:15 is 8 hours. 17:15 to 17:40 is 25 minutes. That makes 8 hours 25 minutes. Take off the break.
7 hours 55 minutes = 7.92 decimal hours
If the end time is earlier than the start time, the tool assumes you worked past midnight. A shift from 22:00 to 06:00 counts as 8 hours, not minus 16.
Time and a half calculator
Time and a half means 1.5 times your normal hourly rate. Double time means 2 times. Here is what that looks like at common rates:
| Normal rate | Time and a half | Double time |
|---|---|---|
| $12.00 | $18.00 | $24.00 |
| $15.00 | $22.50 | $30.00 |
| $20.00 | $30.00 | $40.00 |
| $25.00 | $37.50 | $50.00 |
| $30.00 | $45.00 | $60.00 |
How to work out time and a half pay in three steps:
- Use this calculator to get your overtime hours in decimal form.
- Multiply your normal rate by 1.5.
- Multiply the two numbers. 4.5 overtime hours at $20 is 4.5 × $30 = $135.
Decimal to time calculator (decimal time converter)
Timesheets and payroll systems often want decimal hours. Divide the minutes by 60 and add them to the hours. To go back, multiply the decimal part by 60.
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 5 | 0.08 | 35 | 0.58 |
| 10 | 0.17 | 40 | 0.67 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.33 | 50 | 0.83 |
| 25 | 0.42 | 55 | 0.92 |
| 30 | 0.50 | 60 | 1.00 |
So 7 hours 45 minutes is 7.75 hours. And 8.4 hours is 8 hours 24 minutes (0.4 × 60 = 24).
Speed distance time calculator and average time
To find an average time, add the times together with this calculator, then divide by how many there are. Three runs of 25:30, 26:10 and 24:50 add up to 76:30. Divide by 3 and the average is 25:30.
For trips, time = distance ÷ speed. A 150-mile drive at 60 mph takes 2.5 hours, or 2 hours 30 minutes. The arrival time calculator turns that into a clock time, and the velocity calculator solves for speed.
Elapsed time calculator: start and end times
Elapsed time is how much time passes between a start and an end. Choose Time between two clock times above, enter both, and the tool does the borrowing for you. By hand: 8:45 am to 3:20 pm is 6 hours 35 minutes, because 8:45 to 2:45 is 6 hours and 2:45 to 3:20 is 35 more minutes.
It works as an add time calculator and a time adder too: pick Add two durations to total up hours and minutes from several tasks or video clips.
Time clock calculator with lunch
For a timesheet, work out the time between clock-in and clock-out, then subtract the unpaid break. In at 8:30 am, out at 5:15 pm, with a 30-minute lunch:
- 8:30 am to 5:15 pm = 8 hours 45 minutes.
- Minus 30 minutes lunch = 8 hours 15 minutes.
- For payroll, convert to decimal: 15 ÷ 60 = 0.25, so 8.25 hours.
Repeat for each day and add the totals with Add two durations to calculate hours and minutes worked for the week.
Marathon pace chart: 5K, 10K, half and full marathon
Running at a steady pace per mile, here is your finish time for each race distance:
| Pace per mile | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|
| 7:00 | 21:45 | 43:30 | 1:31:46 | 3:03:32 |
| 8:00 | 24:51 | 49:43 | 1:44:53 | 3:29:45 |
| 9:00 | 27:58 | 55:55 | 1:57:59 | 3:55:58 |
| 10:00 | 31:04 | 1:02:08 | 2:11:06 | 4:22:11 |
| 11:00 | 34:11 | 1:08:21 | 2:24:12 | 4:48:24 |
| 12:00 | 37:17 | 1:14:34 | 2:37:19 | 5:14:38 |
To use this as a marathon time calculator for any other pace, multiply your pace by the distance: 26.22 miles for a marathon, 13.11 for a half, 6.21 for 10K and 3.11 for 5K. The 10K pace chart rows above assume an even pace the whole way.
Other ways to use this calculator
Hours, minutes and decimal time in one place.
- Time card and timesheet calculator — use Time between two clock times for each shift, with the unpaid break.
- Decimal time calculator and converter — the result shows decimal hours alongside hours and minutes.
- Average time calculator — add the times, then divide by how many there are.
- 8 hour shift calculator — see how to calculate hours between two times.
- Time and a half calculator — see how much time and a half is.
- Hours calculator — total up hours and minutes across several shifts.
- Subtract time — choose subtract to take one duration away from another.
Related guides
Frequently asked questions
Convert both to a single unit, add, then convert back — because time is base 60, not base 10. For 2h 45m plus 1h 50m: that is 9,900 plus 6,600 seconds, giving 16,500, which is 4 hours 35 minutes. Adding 2.45 and 1.50 as ordinary decimals gives 3.95, which is wrong. The calculator handles the conversion in both directions.
When a shift crosses midnight the end time reads lower than the start, so add 24 hours to the end before subtracting. A 22:00 to 06:30 shift becomes 30:30 minus 22:00, giving 8 hours 30 minutes. Simple subtraction would return −15.5, which is meaningless. This calculator does it automatically in "between" mode — just remember to deduct unpaid breaks.
Decimal hours express minutes as a fraction of an hour, which is what payroll systems multiply by an hourly rate. Thirty minutes is 0.5 hours, 15 minutes is 0.25, and 20 minutes is 0.333. Divide minutes by 60 to convert — do not just move the decimal point. Writing 7h 30m as 7.30 instead of 7.5 is the most common and costly timesheet error there is.
Divide the minutes by 60. So 45 minutes is 45 ÷ 60 = 0.75 hours, and 20 minutes is 0.333. Useful ones to memorise: 15 minutes is 0.25, 30 is 0.5, and 45 is 0.75. The mistake to avoid is treating the minutes as decimals directly — 7 hours 30 minutes is 7.5 decimal hours, never 7.30.
Pick 'Time between two clock times' and enter the start and end. The calculator shows the elapsed hours and minutes and the decimal hours. If the end is earlier than the start, it counts the time past midnight.
Multiply your normal hourly rate by 1.5, then multiply by your overtime hours in decimal form. At $20 an hour, time and a half is $30, so 4.5 overtime hours pays $135.
Divide the minutes by 60 and add the result to the hours. 7 hours 45 minutes is 7 + 45/60 = 7.75 hours. To convert back, multiply the decimal part by 60.
Find the time between clock-in and clock-out, then subtract the unpaid break. 8:30 am to 5:15 pm is 8 hours 45 minutes; minus a 30-minute lunch gives 8 hours 15 minutes, or 8.25 hours in decimal for payroll.
About 4 hours 22 minutes. A marathon is 26.22 miles, so 26.22 times 10 minutes is 262.2 minutes. A 9-minute mile pace finishes in about 3 hours 56 minutes.
Sources and further reading
- NIST — Time and frequency division — civil timekeeping standards
- US Department of Labor — Overtime pay under the FLSA — the time-and-a-half rule referenced above
- BIPM — The International System of Units (SI Brochure) — the second, minute and hour as units of time
- US Department of Labor — Overtime pay — federal time-and-a-half rules