GeoPunk – geographic tools for Great Britain

Time Calculator

Add or subtract hours and minutes from a time, work out the time between two times (even overnight), total up several durations, convert decimal hours, calculate work hours minus a break, or add/subtract days, months and years from a date.

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Time Calculator

Try:

Time fields use your device's native time picker (12-hour or 24-hour, depending on your system settings). Use the toggle above to choose how results are displayed - your choice is remembered on this device.

More Time Calculations

Try:
Hours & minutes
Total minutes
Decimal hours

Add up several time lengths - useful for timesheets, travel legs, exercise sessions or video lengths. Click the +/− button on a row to subtract that duration instead, e.g. to take off a break.

Try:
Hours & minutes
Total minutes
Decimal hours
Try:
Total minutes
Total hours
Total days

Hours & Minutes → Decimal

Decimal Hours → H & M

Minutes → Hours & Minutes

Try:
Hours & minutes
Total minutes
Decimal hours

Date Calculator

ISO date
Day of week
Day of year
ISO week number
Total days
Total weeks
Total months (approx.)

How to use the Time Calculator

The calculator at the top of the page handles the quick sums you'd otherwise do in your head - working out what time a meeting ends, what time a shift started, or what time it'll be in a few hours. Type a start time such as 18:30, add 7 hours and 45 minutes, and the tool shows 02:15 - flagging that it falls on the following day, since the calculation crosses midnight.

Below the main calculator, five more tools cover the calculations that come up less often but still regularly: the time between two clock times (including overnight spans), adding several durations together, the elapsed time between two full dates and times, converting between minutes, hours-and-minutes and decimal hours, and working out hours worked once a break is taken off. Every tool has clickable examples so you can see how it works before typing your own numbers.

Working Out the Time Between Two Times

Finding the gap between two clock times is only unambiguous once you know which day the end time falls on. 22:15 to 06:40 could mean 8 hours 25 minutes overnight, or a negative span if both times were meant to be on the same day. The Time Between Two Times tab makes this explicit with an "Ends the next day" tick box, so the result is never guesswork - and if you forget to tick it when you should have, the tool tells you the result is negative and why.

Adding Durations and Converting Decimal Hours

Timesheets, payroll systems and travel itineraries often need durations combined or converted between formats. The Add Several Durations tab totals up any number of hours-and-minutes entries, with an option to subtract individual rows (handy for taking off a break). The Convert Minutes / Decimal Hours tab moves between the three formats people actually use: raw minutes (135 minutes), hours and minutes (2 hours 15 minutes), and decimal hours (2.25) - the format most payroll spreadsheets expect.

Work Hours, Breaks and Multi-Day Durations

The Work Hours (Shift & Break) tab takes a shift start and finish time and a break length in minutes, and returns hours actually worked - with an overnight option for shifts that finish after midnight. For longer spans that cross several days, the Date & Time Difference tab takes a full start date and time through to a full end date and time and returns the result in days, hours and minutes, useful for project durations, travel time or elapsed time between events.

Date Calculator

Separate from time-of-day maths, the Date Calculator section works in calendar days, weeks, months and years rather than hours and minutes. Use Add / Subtract Date for questions like "13 days from today" or "what date was 6 months ago", and Date Difference for the exact calendar gap between two dates - broken down into years, months and days, which also makes it useful as an age calculator. All date arithmetic is calendar-aware, so leap years and varying month lengths are handled automatically.

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Frequently Asked Questions

Use the Time Calculator at the top of the page: set the start time to 18:30, enter 7 hours and 45 minutes, choose Add, then click Calculate. The tool shows 02:15 and flags that this falls on the following day, since 18:30 + 7h45m crosses midnight.

Open the Time Between Two Times tab, enter the start and end times, and tick "Ends the next day" so the calculation knows the end time falls on the following morning rather than earlier the same day. 22:15 to 06:40 the next morning comes to 8 hours 25 minutes.

Open the Add Several Durations tab, enter each duration in hours and minutes (adding more rows as needed), then click Calculate Total. Use the +/− button on a row to subtract a duration instead of adding it - useful for taking off a break or unpaid time.

Open the Convert Minutes / Decimal Hours tab. To convert raw minutes, use the "Minutes to Hours & Minutes" box - 135 minutes converts to 2 hours 15 minutes. To convert to or from decimal hours (common in timesheets and payroll), use the other two boxes - for example 7 hours 30 minutes equals 7.5 decimal hours, and 6.75 hours equals 6 hours 45 minutes.

Open the Work Hours (Shift & Break) tab, enter the shift start and finish times and the length of the break in minutes, then click Calculate. A shift from 08:35 to 17:10 with a 45-minute break comes to 7 hours 50 minutes worked. Tick "Finishes the next day" for overnight shifts.

Yes. The Date & Time Difference tab takes a full start date and time and a full end date and time, and returns the elapsed duration in days, hours and minutes - for example, 15 July 2026 at 18:30 to 18 July 2026 at 09:15 comes to 2 days, 14 hours and 45 minutes.

Open the Date Calculator section and use the Add / Subtract tab. Pick a starting date, enter an amount, choose the unit (days, weeks, months or years) and whether to add or subtract, then click Calculate. Calendar-aware arithmetic means leap years and varying month lengths are handled automatically.

Yes. In the Date Calculator section, open the Date Difference tab, enter the date of birth in From and today's date in To, then click Calculate. The years, months and days shown give an exact age breakdown.
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