Time & Date
Calculate the duration between two times, accounting for overnight spans.
Duration
8h 30m
From 09:00 to 17:30
If your end time is earlier than your start time, it will be treated as the next day.
A time duration calculator computes the elapsed time between a start time and an end time, returning the result in hours, minutes, and seconds (or as a decimal total). It handles single-day durations and can account for same-day or multi-day spans, making it useful for project tracking, fitness logging, or charging by the hour.
The calculator subtracts the start time from the end time to find the difference. If both times fall on the same day, the math is straightforward: just subtract minutes and hours. If the span crosses midnight or multiple days, the tool adds 24 hours (86,400 seconds) for each day elapsed. The result is then formatted into a human-readable display showing total hours, remaining minutes, and seconds—or optionally as a single decimal (e.g. 2.75 hours).
Duration (in seconds) = (End time – Start time) in seconds; then convert to hours:minutes:seconds formatEnd time and start time are measured from midnight (00:00) in seconds. Subtract start from end to get the raw duration in seconds, then divide by 3,600 for hours, divide the remainder by 60 for minutes, and the final remainder is seconds. If the result is negative (end time earlier than start time on the same day), add 86,400 seconds (one full day).
| Input | Result | Notes |
|---|---|---|
| Start: 09:15, End: 17:45 | 8 hours 30 minutes | Common workday duration from mid-morning to late afternoon |
| Start: 14:20, End: 14:47 | 27 minutes | Short interval, useful for timing a quick meeting or workout set |
| Start: 23:30, End: 01:15 (next day) | 1 hour 45 minutes | Span crossing midnight; calculator adds 24 hours to handle overnight shifts |
Yes. If your end time is on a later day, enter the full date and time, or simply note that the result will show the total span (e.g. 30 hours 45 minutes for a span from 8 AM Tuesday to 2:45 PM Wednesday).
This means your end time is earlier than your start time on the same calendar day. Either the end time is actually on the next day, or you entered them in the wrong order. Swap them or add 24 hours to the end time.
Yes. Enter your clock-in time as the start and clock-out time as the end. The result is your total hours worked that day. For a full week, calculate each day and sum them.
No. This calculator works with clock times only. If you span a daylight saving transition, your true elapsed time may differ from the clock time shown by one hour.
24-hour format (military time) is clearer and eliminates AM/PM confusion. For example, use 14:30 instead of 2:30 PM, especially for overnight shifts.
Not with this tool alone. Calculate each pair separately, then sum the results in a spreadsheet or calculator for your total.