Add or subtract days, hours, minutes and seconds, move a date and time forward or back, or calculate a time expression.
Leave any field blank to count it as 0.
| Unit | Total |
|---|---|
| Seconds | |
| Minutes | |
| Hours | |
| Days |
Start from a date and time, then add or subtract days, hours, minutes and seconds to get the new date and time.
Type values with d, h, m, s and join them with + or −. Example: 1d 2h 3m 4s + 4h 5s - 2030s
| Unit | Total |
|---|---|
| Seconds | |
| Minutes | |
| Hours | |
| Days |
Convert every value to seconds (1 day = 86,400 s, 1 hour = 3,600 s, 1 minute = 60 s), add or subtract, then convert back to days, hours, minutes and seconds. Example: 1 d 2 h 3 m 4 s + 4 h 5 s = 1 day 6 hours 3 minutes 9 seconds.
The Time Calculator adds and subtracts amounts of time. Use it for timesheets and payroll hours, shift lengths, project estimates, cooking or travel times, video and audio durations, or any sum such as “2 hours 45 minutes plus 3 hours 30 minutes”.
It contains three tools. The first adds or subtracts two time values entered as days, hours, minutes and seconds. The second starts from a date and clock time and moves forward or backward by an amount of time. The third accepts an expression like 1d 2h 3m 4s + 4h 5s − 2030s and evaluates it. Blank fields count as zero, and every calculation runs in your browser.
For the time between two dates, use the Age Calculator; to convert a clock time between cities, use the Time Zone Calculator.
Time is not decimal — 60 seconds make a minute and 24 hours make a day — so the calculator converts everything into one unit (seconds), does the arithmetic there, and converts back.
Daylight saving: the date-and-time tool works in plain clock time, with no time zone, so it never adds or removes an hour for daylight saving. If your two times fall in different zones, convert them first with the Time Zone Calculator.
| First value | Op | Second value | Result |
|---|---|---|---|
| 1 day 2 hours 3 minutes 4 seconds | + | 4 hours 5 seconds | 1 day 6 hours 3 minutes 9 seconds |
| 8 hours 45 minutes | + | 3 hours 30 minutes | 12 hours 15 minutes |
| 1 day | − | 5 hours 30 minutes | 18 hours 30 minutes |
| 1 hour 30 minutes | + | 1 hour 15 minutes | 2 hours 45 minutes |
| 2 days | − | 2 days 1 second | −1 second |
These are the standard relationships the calculator uses.
| Unit | Equals |
|---|---|
| Millisecond | 0.001 second |
| Second | Base unit of time (SI) |
| Minute | 60 seconds |
| Hour | 60 minutes = 3,600 seconds |
| Day | 24 hours = 1,440 minutes = 86,400 seconds |
| Week | 7 days = 604,800 seconds |
| Common year | 365 days = 31,536,000 seconds |
| Leap year | 366 days = 31,622,400 seconds |
| Average Gregorian year | 365.2425 days |
| Month | 28 to 31 days (Feb: 28, or 29 in a leap year) |
| Decade / Century / Millennium | 10 / 100 / 1,000 years |
Timesheets often need minutes as decimal hours (for example 1 hour 30 minutes = 1.5 hours). Divide the minutes by 60.
| Minutes | Decimal hours | Rounded to 2 places |
|---|---|---|
| 5 minutes | 0.0833 | 0.08 |
| 6 minutes | 0.1 | 0.10 |
| 10 minutes | 0.1667 | 0.17 |
| 12 minutes | 0.2 | 0.20 |
| 15 minutes | 0.25 | 0.25 |
| 20 minutes | 0.3333 | 0.33 |
| 30 minutes | 0.5 | 0.50 |
| 40 minutes | 0.6667 | 0.67 |
| 45 minutes | 0.75 | 0.75 |
| 50 minutes | 0.8333 | 0.83 |
| 60 minutes | 1 | 1.00 |
Add the minutes first; if they reach 60 or more, carry whole hours over, then add the hours. For example, 2 h 45 min + 3 h 30 min = 6 h 15 min. The calculator does this carrying for you using seconds.
Choose “Subtract (−)”. The second value is taken away from the first. If the second is larger, the answer shows a minus sign (for example −1 hour).
A day has 86,400 seconds, an hour has 3,600 seconds and a minute has 60 seconds.
Divide the minutes by 60. 15 minutes = 0.25 hours, 30 minutes = 0.5 hours and 45 minutes = 0.75 hours. See the conversion chart on this page.
Yes. The number fields and the expression box accept decimals, so 1.5h is the same as 1h 30m.
Numbers followed by d, h, m or s, joined with + or −, for example 1d 2h 3m 4s + 4h 5s − 2030s. Spaces are optional. Anything else is rejected with a message pointing to the problem.
Use the second tool: pick a start date and time, choose add or subtract, enter the days, hours, minutes and seconds, and press Calculate to see the new date, time and weekday.
No. The tool uses plain clock time without a time zone, so it never adds or removes an hour for daylight saving. Use the Time Zone Calculator when zones matter.
Enter the later time as the first value and the earlier time as the second, then choose Subtract. For overnight spans, add 24 hours to the later time first.
Yes. It is free, needs no sign-up, and all calculations happen in your browser — nothing you type is sent or stored.
