Hours Calculator

Time is the one everyday quantity that is not decimal, and that is where timesheet errors come from. Seven hours and forty-five minutes is 7.75 hours, not 7.45 — but typed into a payroll field as 7.45 it silently costs you eighteen minutes. This calculator works in hours and minutes throughout, so you never have to do that conversion in your head: it adds up blocks of time, subtracts one duration from another, and turns a start time, an end time and a break into a total.

Decimal hours versus hours and minutes

Payroll systems, invoices and billing software almost always want decimal hours, because you cannot multiply an hourly rate by “7h 45m.” The conversion is simply minutes ÷ 60:

• 10 minutes = 0.17 hours (0.1666…)
• 15 minutes = 0.25 hours
• 20 minutes = 0.33 hours (0.3333…)
• 30 minutes = 0.5 hours
• 45 minutes = 0.75 hours
• 50 minutes = 0.83 hours

Only minute counts divisible by 6 give a clean decimal, so most conversions repeat and have to be rounded — which is why you should convert once, at the end, rather than converting each day and adding rounded figures. This tool works in whole minutes internally, so no rounding error creeps in along the way. For the final decimal figure, the minute to decimal converter is precise.

Three tabs, two different kinds of time

The distinction that matters is between a duration (how long something took) and a clock time (when it happened). Two tabs handle durations, one handles clock times:

• Add Time — a running list of durations. Type hours and minutes, press + to commit the entry, and the total updates. This is the tab for adding up five task sessions or five short days.
• Subtract Time — one duration minus another: “I am contracted 40 hours and have logged 32h 15m, what is left?” Both sides are durations, not times of day.
• Timesheet — clock in, clock out, break. Enter start and end on a 24-hour clock and the unpaid break in minutes to get the paid time for that shift.

Every result is shown as Xh Ym and normalised — 90 minutes of entries reads as 1h 30m, never 0h 90m.

Overnight shifts, breaks and the 24-hour clock

The Timesheet tab uses a 24-hour clock, so an afternoon finish at 5:30 pm is entered as 17 and 30, not 5 and 30. Enter it as 5 and the tool will read your shift as ending at 5 am.

Overnight shifts are handled automatically: if the end time is earlier than or equal to the start time, the calculator assumes the shift crossed midnight and adds 24 hours, so 22:00 to 06:00 correctly returns 8h 0m. One consequence: identical start and end times are read as a full 24 hours, not as zero.

The break field takes minutes and is always subtracted, so it should hold your unpaid break only — if paid rest breaks count as working time where you are, leave them out. A break longer than the shift floors the result at 0h 0m rather than going negative.

Rounding and the mistakes worth avoiding

• Enter whole numbers. The hour and minute fields read integers, so typing 1.5 into an hours box registers as 1, not 1h 30m. Put the 30 in the minutes box instead.
• Nothing counts until you press +. On the Add Time tab, typing into the boxes does not change the total — the entry has to be committed to the list. The page opens with one 0h 30m entry already there; remove it with the X if you do not want it.
• Subtraction never goes below zero. Subtract more than you started with and the result shows 0h 0m rather than a negative duration, so an unexpected zero usually means the inputs are the wrong way round.
• Some employers round shift times to the nearest quarter hour or similar increment. That is a payroll policy rather than arithmetic, and the rules differ by jurisdiction — this tool reports exact minutes, so a small gap against your payslip may be rounding rather than an error.
• Nothing is saved. Entries live only in the open tab. For hours you need to keep across days, use the work hours tracker.

How to use the Hours Calculator

1. Pick a tab: Add Time, Subtract Time or Timesheet.
2. To add durations: type the hours and minutes for the first block, press +, and repeat for each further block. The running total sits beneath the list, and any entry can be removed with its X.
3. To subtract: enter the starting duration in the top row, the amount to take off in the bottom row, and read the result. It updates as you type.
4. For a shift: enter the start and end hours and minutes on a 24-hour clock, then type the unpaid break in minutes. Enter the break last — the total recalculates from that field, so re-typing it refreshes the result after any change to the start or end time.
5. Convert the final figure to decimal hours only when you need it for pay or an invoice: divide the minutes by 60 and add them to the hours.

Frequently Asked Questions

How do I convert the result to decimal hours for payroll?

Divide the minutes by 60 and add that to the hours. 8h 20m is 8 + (20 ÷ 60) = 8.33 hours. Do this once on the final total rather than on each day's figure.

Can it handle a shift that runs past midnight?

Yes. If the end time is not later than the start time, the Timesheet tab assumes the shift crossed midnight and adds a day. A 23:15 to 07:45 shift with a 30-minute break returns 8h 0m.

Why is my total showing 0h 0m?

On the Subtract tab, because you subtracted more than the starting duration — negative results are floored at zero. On the Timesheet tab, because the break is as long as the shift. On the Add tab, because the list is empty.

Does it calculate overtime or pay?

No. It reports total time only, with no rate, no overtime threshold and no multiplier. Take the total to the overtime pay calculator for the money side.

Can I enter more than 59 minutes in a minute box?

The field is intended for 0–59, and the total is normalised into hours and minutes regardless. Keeping minutes under 60 simply makes the entry list easier to read back.

Do my entries survive a refresh?

No. Everything runs locally in the browser and nothing is stored, so reloading clears the list. Write down or screenshot the total before you close the tab.

Can I subtract two times of day, like 09:15 and 17:40?

Use the Timesheet tab for that, with a break of 0 if there was none. The Subtract tab is for durations, not clock times, and does not know about crossing midnight.