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Subtract Time Calculator

Subtract Time Calculator works out Duration in hours and Duration in minutes from Start time, Start date (optional) and End date (optional). The default figures on this page give resulting time (24 h) of 09:00:00; change any entry and the result, the working and the sources update together.

Resulting time (24 h)
09:00:00
Time Duration Calculator
Duration in hours
0.0000 h
Duration in minutes
0.00 min
Duration in seconds
0 s
Whole days
0 d
Hours part
0 h
Minutes part
0 min
Seconds part
0 s
Duration as h:mm
0:00
Duration as h:mm:ss
0:00:00
Duration in words
0 seconds
Hours after the break
0.0000 h
Break deducted
0 min
Resulting time (12 h)
9:00 AM
Days rolled over
0 d
Crosses midnight
no
Worked out from ISO 8601-1:2019, Date and time - Representations for information interchange, clauses 5.3 and 5.5 and 2 other sources.

Your figures

Updates as you type
Accepts 09:00, 9:00 am or 09:00:30.
Give both dates for spans longer than a day.

How this is worked out

2 steps
  1. Subtracting 0 seconds from 09:00:00.
  2. 0 minutes total = 0 hours (60 s = 1 min, 60 min = 1 h).

Its 10 worked examples are re-run on every release, last on 15 September 2026. What changed

Sources and references

3 sources
ISO 8601-1:2019, Date and time - Representations for information interchange, clauses 5.3 and 5.5
Time-of-day and duration representation: 24-hour clock, sexagesimal minutes and seconds.
BIPM SI Brochure, 9th edition, Table 8 (non-SI units accepted for use with the SI)
1 min = 60 s, 1 h = 3600 s, 1 d = 86400 s - the exact conversions used for the decimal totals.
US Department of Labor, Fact Sheet #22: Hours Worked Under the FLSA
Bona fide meal periods of 30 minutes or more are not work time, which is why the break deduction is separate from the raw span.

What the Subtract Time Calculator calculates

Elapsed time between two clock times, including overnight and multi-day spans, adding or subtracting hours, minutes and seconds from a time, totalling a list of durations such as a playlist or a set of videos, halving or splitting a duration, and rescaling a runtime for playback speed.

How to use this Subtract Time Calculator

Enter Start time, Start date (optional), End date (optional) and Days to add or subtract. Duration in hours updates as you type. Change one figure at a time to see what drives the result.

How the result is worked out

Open “How this is worked out” beside the result for the step-by-step calculation behind Duration in hours, Duration in minutes and Duration in seconds.

The method follows ISO 8601-1:2019, Date and time - Representations for information interchange, clauses 5.3 and 5.5, BIPM SI Brochure, 9th edition, Table 8 (non-SI units accepted for use with the SI) and US Department of Labor, Fact Sheet #22: Hours Worked Under the FLSA.

What you can compare

Change one input at a time to see how it affects Duration in hours, Duration in minutes and Duration in seconds. The inputs you can vary are Start time, Start date (optional), End date (optional), Days to add or subtract, Hours to add or subtract and Minutes to add or subtract.

Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.

Embed this calculator on your website

Copy this code into any page. The calculator appears with the figures currently entered, sizes itself to fit, and a small credit line links back here. Free, no account, no ads inside it, no tracking of your readers. Set your own figures and fixed fields; Personal removes the credit line, sets your colour and shows you which sites use it.

Preview

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Frequently asked questions

How to calculate time subtraction?

Elapsed time between two clock times, including overnight and multi-day spans, adding or subtracting hours, minutes and seconds from a time, totalling a list of durations such as a playlist or a set of videos. Open “How this is worked out” beside the result to see each step for your own figures.

How to subtract minutes from hours?

It needs Start time, Start date (optional), End date (optional), Days to add or subtract, Hours to add or subtract and Minutes to add or subtract. Nothing else is required, and the figures stay in your browser.

How can I calculate time difference?

The result gives Duration in hours, Duration in minutes, Duration in seconds, Whole days, Hours part and Minutes part, each labelled with its unit so the figure can be read on its own.

Is there a time calculator?

Elapsed time between two clock times, including overnight and multi-day spans, adding or subtracting hours, minutes and seconds from a time, totalling a list of durations such as a playlist or a set of videos. Put your own figures in above and the working updates beside the result. For scale, the default figures on this page give 09:00:00.

What information do I need for the Subtract Time Calculator?

You need Start time, Start date (optional), End date (optional), Days to add or subtract, Hours to add or subtract, Minutes to add or subtract and Seconds to add or subtract. The page opens with default figures that give resulting time (24 h) of 09:00:00, so you can see the scale before entering your own.

What does this Subtract Time Calculator show?

It shows Duration in hours, Duration in minutes, Duration in seconds, Whole days, Hours part, Minutes part, Seconds part and Duration as h:mm, with the working and any warnings for your entries.

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