Time Duration Calculator
Pick a start and an end — the exact length between them appears instantly, split into days, hours, minutes and seconds.
How Time Duration Is Worked Out
A duration is the distance between two moments. The reliable way to find it — and the way this calculator works — is to turn both moments into a single count (seconds since a fixed point), subtract, and then split the difference back into days, hours, minutes and seconds. Splitting is repeated division: every 86,400 seconds make a day, every 3,600 an hour, every 60 a minute.
Worked Examples
| From | To | Duration |
|---|---|---|
| 9:00 AM | 5:00 PM (same day) | 8 hours |
| 9:15 AM | 12:45 PM (same day) | 3 hours 30 minutes |
| 10:40 PM | 6:25 AM (next day) | 7 hours 45 minutes |
| Monday 9:00 AM | Wednesday 11:30 AM | 2 days, 2 hours 30 minutes |
| Oct 31, 9:00 AM | Nov 2, 11:30 AM | 2 days, 2 hours 30 minutes (50.5 hours total) |
The overnight row is where pencil maths usually goes wrong: 10:40 PM to midnight is 1 hour 20, midnight to 6:25 AM is 6 hours 25, and the two parts add to 7 hours 45. Setting the end date one day later makes the calculator do that split automatically.
Where Durations Come Up
Shift lengths and timesheets are the everyday case — with the break caveat in the FAQs below. Beyond work: flight and layover lengths, video and recording runtimes, parking and rental bills that charge by the hour, sleep spans, and cooking times that start from a specific clock time. For pure countdowns to a moment rather than the length between two, use the Countdown Timer; for a live elapsed-time measure, the Stopwatch; and for counting whole days to a date, the holiday countdowns such as the Christmas Countdown.
Frequently Asked Questions
How do I calculate the duration between two times?
Subtract the start from the end, borrowing across the units: seconds from seconds, minutes from minutes, hours from hours. 11:30 to 14:45 is 3 hours 15 minutes — 45 − 30 = 15 minutes and 14 − 11 = 3 hours. When the end time is smaller than the start in any unit you borrow from the next one up, exactly like column subtraction at school. This calculator does the borrowing for you, across days as well as within one day.
How do I calculate hours between two times for a work shift?
Enter the clock-in and clock-out times and read the 'total hours' line — a 9:00 AM start and 5:30 PM finish is 8.5 hours. For paid hours, subtract unpaid breaks yourself first: a 30-minute lunch inside that shift means 8.0 paid hours. If your shift runs past midnight, use the date fields — set the end date to the next day and the calculator handles the overnight span correctly.
What is the duration from 9:00 AM to 5:00 PM?
Exactly 8 hours — 480 minutes, or 28,800 seconds. It is the standard full-time shift length in much of the US and UK, which is why it is the most commonly checked duration of all.
How many minutes are in a duration like 2 days 4 hours?
Multiply it out: 2 days is 2 × 24 × 60 = 2,880 minutes, and 4 hours is 240 minutes, for a total of 3,120 minutes. The calculator prints total minutes and total seconds alongside the split-out days/hours/minutes/seconds, so you never need the manual conversion.
Does the calculator handle durations longer than 24 hours?
Yes. Because both a date and a time are entered at each end, spans of days, weeks or months work the same way — the result splits into days plus the remaining hours, minutes and seconds, and also gives the whole span as total hours. The only step that matters is picking the right end date for anything that crosses midnight.
What happens if the end time is earlier than the start time?
The calculator swaps them and tells you it did. A duration is a length, not a direction — 14:00 to 11:30 is the same 2 hours 30 minutes as 11:30 to 14:00. If you meant the span to run overnight instead (11:30 PM to 2:00 AM, say), set the end date to the following day and enter it again.
Is this time duration calculator free?
Yes. It is completely free with no signup required, and it runs entirely in your browser — the times you enter are never uploaded or stored.