How do I add and subtract time durations across units?
Type each duration with its unit on one line, separated by + or -, like "2 days - 4h" or "5h 30m + 2h 15m". The calculator handles mixed units for you, so you never convert to minutes first. Pick a result format such as Hour Minute or Day Hour Minute to read the answer.
Most time math goes wrong at the unit boundaries. You add 50 minutes to 40 minutes and have to remember it rolls past an hour, or you subtract 4 hours from 2 days and stall on the borrow. This tool keeps the units intact. You write the durations the way you say them, mix hours with days with weeks, and it carries and borrows across the boundaries on its own.
Step by step
Write each duration with its unit
Every number needs a unit attached. Use h or hour, m or minute, d or day, w or week, s or second. So you type 2 days, not 2, and 30m, not 30. You can glue parts together like 5h 30m to mean five hours and thirty minutes.
Join durations with + and -
Put a plus to add and a minus to subtract between durations, on one line. Chain as many as you like: 1w 3d + 2 days - 4h is valid. The units can differ at every step, so weeks, days, and hours sit side by side in the same expression.
Let it carry and borrow across units
You do not convert anything to minutes first. Subtract 4h from 2 days and the calculator borrows from the day for you. Add minutes past 60 and they roll into the next hour. The running total stays exact across every unit you mix in.
Choose how the result reads
Pick a format from the picker. Hour Minute gives an answer like 7 Hours 45 Minutes. Day Hour Minute breaks a long total into days and hours. Week Day groups it into weeks. The same expression can be read in whichever unit fits.
Worked examples
5h 30m + 2h 15m=7 Hours 45 MinutesAdding two hour-and-minute durations; the minutes carry past 60 cleanly.
2 days - 4h=1 Day 20 HoursSubtracting hours from days borrows across the unit boundary, no conversion needed.
1 day + 12h 30m=1 Day 12 Hours 30 MinutesMixing a whole day with hours and minutes in one expression.
1w - 2d=5 DaysSubtracting days from a week, read back in week and day terms.
Try it yourself
Type hours, minutes, days, weeks, months, years, or seconds, as full words or shorthand (h m d w), with + - * /. Pick how the answer reads with Show result as up top. It all runs in your browser. Drag the card’s right edge to make it wider.
Common questions
Do I have to convert everything to minutes first?
No. That is the point. You can write 2 days - 4h directly and the calculator borrows across the day, hour, and minute boundaries for you. Each number keeps its own unit, and the running total stays exact no matter which units you mix.
Can I mix hours, days, and weeks in the same calculation?
Yes. An expression like 1w 3d + 2 days - 4h is valid. Units can differ at every step. The calculator combines them into one total, then shows it in whatever result format you pick, such as Day Hour Minute or Week Day.
Why does my result show a decimal in some formats?
A format only carries down to its smallest listed unit. If you choose Week Day and the total has a leftover smaller than a day, it appears as a fraction of a day. Switch to Day Hour Minute or Hour Minute to see that remainder as whole hours and minutes.
A scheduler blocks out two full days for a task, then trims four hours for a meeting and needs the remaining duration without doing the borrow in their head.