Time Duration Calculator

How to use the time duration calculator

Add and subtract durations

1. In Durations (one per line), type or paste your durations, one per line. The box starts with an example you can replace.
2. Start a line with a minus sign to subtract it (a lunch break, for example). Lines starting with # are notes and are ignored.
3. The results update as you type (or click Calculate): the Total (h:mm:ss), the Hours and minutes, the Decimal hours, the Total minutes and, above 24 hours, the total In days. Clear empties the list and Copy copies the total.

Time between two times

1. Enter a Start time and an End time, with seconds if you need them.
2. Read the Elapsed time in h:mm:ss, in hours and minutes, in decimal hours and in minutes.
3. If the end time is earlier than the start time, the tool assumes the period crosses midnight (a night shift from 22:30 to 06:15 lasts 7 h 45 min) and tells you so.
4. Add to the list above copies the result into the durations list, so you can add up several shifts or sessions.

Accepted formats

Each line can use any of these forms:

• clock style: 7:45, 1:02:03 (hours can go past 24, such as 38:30);
• units: 2h 30m, 1h30, 90 min, 45 s, 1 d 2 h, or unit words such as 2 hours 15 minutes (the words of the other site languages work too, e.g. French 2 heures 15);
• a plain decimal number of hours: 7.5 or 7,5.

Units must go from large to small (hours, then minutes, then seconds). A line that can’t be read is shown in the message under the buttons and left out of the total, so a typo never silently changes your result.

Decimal hours for timesheets

Payroll and invoicing software usually wants hours as a decimal number, not in hours and minutes. The conversion is:

decimal hours = hours + minutes ÷ 60 + seconds ÷ 3600

So 7 h 45 min is 7 + 45 ÷ 60 = 7.75 hours, and 8 h 20 min is 8.33 hours (rounded). A common mistake is to write 7 h 45 min as “7.45”: that is 18 minutes short. The Decimal hours result is rounded to two decimals; for billing, multiply the unrounded minutes (Total minutes ÷ 60) by the hourly rate for the most accurate amount.

Common conversions: 15 min = 0.25 h, 30 min = 0.5 h, 45 min = 0.75 h, 10 min ≈ 0.17 h, 20 min ≈ 0.33 h.

Example: a working week

Enter the five days 7:45, 8:15, 7:30, 8:00 and 6:50, then -0:30 for an unpaid break you forgot to take off. The total is 37:50:00, or 37 h 50 min, which is 37.83 decimal hours.