Decimal to Time

Decimal Hours Calculator

Add and subtract decimal hours, H:MM times and minutes. You get one exact total in decimal hours and in hours and minutes, rounded once at the end.

LinesExample loaded

Up to 100 lines. Use + and − on each row; do not type a minus in the value. Nothing is uploaded.

Total · decimal hoursExact

22.35 hours

Total · timeExact

22:21

How this total was calculated
  1. Add 7.75 hRunning total: 7.75 h (7:45)
  2. Add 8.1 hRunning total: 15.85 h (15:51)
  3. Add 6.5 hRunning total: 22.35 h (22:21)

Exact integer mathRuns in your browserNothing you type is uploaded

How the calculator adds and subtracts

Each line is parsed strictly, converted to an exact value, and kept that way until the total is formatted. Rounding happens once on the total, not on every row, so the answer does not drift when you add many small entries. For how rounding is applied elsewhere, see the rounding guide and the Calculation Method page.

Need one value converted? Use Decimal to Time or Time to Decimal. Need a whole column? Try the Bulk Converter.

Adding hours and minutes: carry at 60

Clock times carry at 60, not 100. On this page, 1:45 + 2:30 = 4:15 (4.25 hours), not 3:75 and not 3.75 hours from adding the minutes as decimals. The same rule applies when you mix formats on one total.

What this calculator does not do

This is not a timesheet: no start and end times, no breaks beyond what you enter as a − line, no overtime or pay rules, and no time zones. It only adds and subtracts durations you type. Negative numbers in the value box are not accepted. Use the − operator on the row.

For tenths-of-an-hour billing steps, see the Tenths of an Hour Chart.

Questions

How do I add hours and minutes?

Add a line for each duration. Choose H:MM for clock times like 7:45, or decimal hours like 7.75. Pick + on each line you want in the total. The answer shows decimal hours and H:MM together.

How do I add decimal hours?

Set the format to Decimal hours and type each value with a period, such as 7.75 and 8.10. Mixed lines are fine: 7:45 on one row and 0.5 on the next gives 8.25 hours.

How do I subtract a lunch break?

Keep your worked time on + lines and add another line with − and the break length, for example 8:00 plus and 0:30 minus. The total updates in both decimal hours and clock time.

Can the total be negative?

Yes. If you subtract more than you add, the total shows a minus sign in decimal hours and in clock time, with a short note. That is a normal result, not an error.

Why not just add the rounded numbers?

Each line is kept at full precision and the total is rounded once, so the answer does not drift. Sixty lines of one minute total exactly 1.00 hour here, not 1.20 from adding 0.02 sixty times.

Can I type a negative number?

No. Negative values in the box are flagged. Use the − operator on the line instead so the sign is explicit.

How many lines can I add?

Up to 100 lines in one run. Blank lines are ignored; error lines stay visible but are left out of the total.

Is my data uploaded anywhere?

No. Everything runs in your browser. Nothing you type is sent to a server or included in analytics.