Time Duration Calculator

How the duration is calculated

Each time is converted to minutes after midnight — 14:30 becomes 870 — and the start is subtracted from the end. Without dates, a negative result means the end time is on the next day, so 24 hours (1,440 minutes) are added: 22:15 to 01:45 is 3 hours 30 minutes. With dates, the calculator adds 1,440 minutes for every calendar day between them, so spans of any length work.

minutes = (end time − start time) + 1,440 × (end date − start date)
decimal hours = minutes ÷ 60

Times use the 24-hour clock internally, but the browser's time picker displays them in your preferred 12- or 24-hour format. Seconds are supported if your picker or typed value includes them.

Worked examples

Example 1: a meeting

09:40 to 11:15 is 675 − 580 = 95 minutes, which is 1 h 35 min, or 1.5833 decimal hours.

Example 2: overnight sleep

22:30 to 06:15: 375 − 1,350 is negative, so add 1,440 to get 465 minutes, which is 7 h 45 min (7.75 hours).

Example 3: across several days

From 2026-10-20 08:00 to 2026-10-23 17:30 is 3 days plus 9 h 30 min, which the calculator shows as 3 days 9 h 30 min — 81.5 hours or 4,890 minutes.

How to read the result

The headline gives the duration in days (when there are any), hours and minutes. The coloured bar shows the span on a 24-hour day when you have not entered dates; an overnight span appears as two segments, before and after midnight. The table repeats the result as decimal hours, total minutes, total seconds and H:MM, which is the format most spreadsheets accept. If the end comes before the start when dates are entered, the result says so and shows the size of the gap.

Hours and minutes versus decimal hours

Clock time is base 60 and decimals are base 10, which causes frequent mistakes. One hour and thirty minutes is 1.5 hours, not 1.3. To convert minutes to a decimal, divide by 60; to go back, multiply the decimal part by 60 — 2.4 hours is 2 hours 24 minutes. Billing, payroll and many apps use decimals, while schedules use clock time. The table shows both so you can paste the right one.

Daylight saving and time zones

This tool measures wall-clock time: the difference between the times shown on a clock. If a daylight-saving change happens inside the interval, the real elapsed time is an hour more or less — a night shift from 22:00 to 06:00 on the night clocks go back lasts 9 real hours. Likewise, if the start and end are in different time zones, convert both to one zone before entering them. For flights, use the local departure and arrival times converted to the same zone.

Common uses

People use a duration calculator to time workouts and runs, measure sleep, check how long a meeting or class lasted, log billable time, work out cooking and baking times, calculate parking or babysitting charges, and plan travel connections. For a whole week of shifts with breaks and overtime, the time card calculator totals everything at once. To turn hours into days or weeks, use the time unit converter, and to count whole days between dates the days between dates calculator.

Limits

Enter both dates or neither: with only one date, the calculator cannot know which day the other time belongs to and asks you to fill in both. Without dates, intervals are always less than 24 hours. Dates from year 1 to 9999 are supported. Durations are exact to the second; the decimal-hours figure is rounded to four places for display.

Adding up several durations

To total several intervals — a series of practice sessions, film running times or support calls — work out each one here and add the decimal hours or total minutes, rather than adding hours and minutes separately and carrying by hand. For example, 1 h 35 min, 2 h 50 min and 0 h 55 min are 95, 170 and 55 minutes, totalling 320 minutes or 5 h 20 min. If the intervals are work shifts with breaks, the time card calculator does the whole sum in one go.

When reporting a total, say which format you are using. "5.20 hours" and "5:20" look alike but differ by 8 minutes: 5.20 hours is 5 hours 12 minutes, while 5:20 is five hours and twenty minutes, or 5.3333 decimal hours. Timesheets, invoices and spreadsheets that mix the two formats are a frequent source of small billing errors that add up over a month.