Two time tools in one page: find the exact duration between two dates and times — for timesheets, shifts, or how long an event ran — or add and subtract hours, days, and minutes from any starting point. Everything updates live as you type, and it all runs locally in your browser.
Time duration between two points
Add or subtract time from a date
How it works
The duration calculator takes both date and time for each endpoint, so it handles overnight shifts, multi-day spans, and partial hours with the same ease. The result shows the gap broken into days, hours, minutes, and seconds — plus the totals in plain hours, minutes, or seconds, which is usually what a timesheet actually wants. If the second point is earlier than the first, the size of the gap is still shown, with a note that the range runs backwards.
Everyday examples
Shift length: 8:00 AM to 5:00 PM → 9 hours, 540 minutes. Overnight: 10:30 PM to 6:15 AM → 7 hours, 45 minutes. On-call window: Friday 5:00 PM to Monday 8:00 AM → 2 days, 15 hours. For planning in the other direction, the add/subtract tool answers questions like “what’s 90 minutes after 2:20 PM?” or “what date is 45 days from today?” — set the start to today’s date and read the result.
Details worth knowing
Times are interpreted in your device’s local timezone, which is what you want for schedules and shifts — the daylight saving shift in November and March is handled correctly, so a 9-hour overnight shift that crosses the spring forward date reads as 8 hours. Fractional values are accepted in the add/subtract fields (0.5 days = 12 hours), and seconds can be included for precise intervals. Everything is computed in plain JavaScript in your browser — no accounts, no tracking, and nothing you enter leaves your device.