Time Calculator

Written byOleh Soloninupdated 25 September 2026

What to work out

Durations, one per line

Hours:minutes or hours:minutes:seconds; a minus at the start subtracts. A number without a colon is decimal hours: 1.5 = 1:30.

Result

Total5:05
In decimal hours5.08
In minutes305
Lines added3

Base-60 arithmetic, handled for you

Add or subtract durations in hours and minutes without decimal confusion. Because 1.5 hours is 1:30, not 1:50.

Time does not count in tens. Sixty minutes to the hour means 45 + 45 gives 1:30, not 90-something, and mental arithmetic goes wrong fast.

This handles carrying across the hour boundary, which is where most manual timesheet errors come from.

How to use

Choose the mode: add up durations, or move a clock time forward or back.
For durations, enter one per line — 1:45, 0:30:15 or a decimal such as 1.5; for clock time, enter the start time and the hours and minutes to add or subtract.
Read off the total in hours and minutes, in decimal hours and in minutes, or the resulting clock time and which day it falls on.

Durations and clock times

Each row is a separate run. Durations can run past 24 hours; clock times wrap round midnight and report the day.

Every row comes from the calculator on this page.
Mode	Input	Result
Add durations	1:45 + 2:30 + 0:50	5:05
Add durations	20:00 + 10:00	30:00, which is 1 day 6 h 0 min
Clock time	22:30 + 3 h	01:30, 1 day later

What this calculator shows

The total duration in hours and minutes
Addition and subtraction of time spans
Correct carrying when minutes pass 60

What to keep in mind

In duration mode results can exceed 24 hours; clock-time mode wraps at midnight and says which day the result falls on.
Decimal hours and clock notation are different: 2.75 hours is 2:45.

FAQs

How do I convert decimal hours to minutes?

Multiply the whole figure by 60: 2.75 hours is 165 minutes. For hours and minutes, keep the whole hours and multiply only the fraction: 2.75 hours is 2:45. Payroll systems use decimals; clocks do not.

What is 1.5 hours in hours and minutes?

1 hour 30 minutes. Reading it as 1:50 is the classic mistake, and it inflates a timesheet by twenty minutes.

Can the total go past 24 hours?

Yes, in the durations mode, so 30:00 is a valid answer for a long project total. The clock mode wraps past midnight and tells you which day you land on.

Does it handle seconds?

Yes, when adding durations: write hours:minutes:seconds, such as 0:30:15. If any line has seconds, the total shows them too.

What is 20:00 plus 10:00?

As durations, 30:00 — 1 day 6 hours, or 30 decimal hours. The total does not wrap, because you are adding stretches of work, not reading a clock.

What time is it 3 hours after 22:30?

01:30 the next day. In the clock mode the calculator wraps round midnight and notes that you have moved one day later.

Worked example

Three tasks in an afternoon

Input: 1:45 + 2:30 + 0:50

Output: 5:05

Note: The minutes total 125, which carries as two hours and five minutes. Adding the columns separately is exactly where people slip.

Useful links

All tools in Date & Time World Clock Time Difference

Time Calculator

Result

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