Date & Time
Time Duration Calculator
Time Duration Calculator is a browser-based calculator tool on CalcToolsBase. Free, browser-based Time Duration Calculator with instant, clearly-labelled results. No signup, no uploads. To use it, enter your values and view the result directly in your browser — no signup and nothing to install.
Use Time Duration Calculator to add up or measure time: give it your start of period and end of period, press Calculate, and read off the total duration — all worked out on your device.
About this calculator
Time Duration Calculator makes it easy to add up or measure time. Enter your start of period and end of period, and it uses clock arithmetic to show the total duration instantly. Everything is computed in your browser, for both speed and privacy.
Designed for shift workers and anyone logging hours, it returns the total duration the moment you calculate — no sign-up, no uploads, and nothing stored between visits.
How to use
- Enter the start time in HH:MM.
- Enter the end time in HH:MM.
- Press Calculate to measure the duration.
- Read the duration in hours, minutes, and decimal hours.
Why use Time Duration Calculator
Fast
Calculations run in your browser. No round trip to a server.
Private
Your inputs never leave your device. Nothing is uploaded.
Free
No signup, no paywall, no ads-in-results, no watermarks.
Accurate
Adds and subtracts clock times to the minute, including breaks and overnight spans. Double-check shift starts, break times and rounding before relying on the result.
Mobile-ready
Optimised for phones, tablets, and desktops alike.
Transparent
Honest disclaimers wherever browser limits or regional rules apply.
Common uses
Time Duration for shift-length and work-log totals
Time Duration when measuring the hours between two times
Time Duration for elapsed-time checks
Time Duration when checking how long something ran
Time Duration for billable-hours logging
Time Duration for a study or practice session
Technical notes
Time Duration Calculator returns the elapsed duration between two times in hours and minutes.
Durations use the start and end times you enter and do not adjust for time zones or daylight saving unless a field asks.
Because it runs locally, results appear instantly with no server round-trip.
FAQ
Can it span midnight?
Yes. When the end time is before the start, the duration is assumed to cross midnight and 24 hours are added.
What happens if a time is blank?
Both times are required; leaving one blank returns a clear prompt rather than a zero result.
What units are returned?
You get hours and minutes, the total minutes, and the total decimal hours.
Does the Time Duration Calculator send my data to a server?
No. The Time Duration Calculator runs entirely in your browser — your inputs never leave your device, and nothing is uploaded or stored.
Worked example
Between 22:30 and 06:15 the next morning is 7 h 45 min (crossing midnight).