TimerPlanTime duration calculator
Time duration
Time between
—h:mm
Given in hours and minutes, and in decimal hours — the two are not the same number.
- Decimal hours—
- Minutes—
- Seconds—
- In words—
One thing a month worth timing
MonthlyOne thing a month worth measuring or capping with a clock — a payroll trap, a nap length, a meeting that never gets added up. Two sentences and the tool.
Try also
How long is it between two times?
The TimerPlan duration calculator gives the gap between two clock times in five forms at once — h:mm, decimal hours, minutes, seconds and words — because the same eight and a half hours is written 8:30 on a clock, 8.5 on a timesheet and 510 minutes in a scheduling tool. Getting the right form is usually more of a problem than getting the right number.
A second time earlier in the day than the first is read as crossing midnight rather than as a negative span, so 22:00 to 06:00 is eight hours. Subtraction alone gives minus sixteen, which is what a spreadsheet returns unless it has been told the dates.
Nothing here is rounded. The exact figure is what any rounding policy should be checked against, and rounding belongs on a timesheet rather than in the arithmetic.
The forms this page produces, and where each one belongs:
| Form | Example | Used by |
|---|---|---|
| h:mm | 8:30 | Clocks, rotas, anything read by a person |
| Decimal hours | 8.5 | Payroll, invoices, hourly rates |
| Minutes | 510 | Scheduling systems, parking, cooking |
| Seconds | 30 600 | Video and audio, frame counts |
| Words | 8 hours 30 minutes | Reading aloud, writing up |
The middle two are where the arithmetic goes wrong most often: 8:30 typed into a decimal field claims eight hours and eighteen minutes, and 8.5 read as a clock time is not a time at all.
With an unpaid break and a number of days, this becomes the hours calculator; a week of shifts is the time card calculator. To go the other way — a start time plus a length — use the time calculator, and to convert a raw number of seconds or minutes into every other unit, the seconds to minutes converter does it in one step.
Frequently asked questions
Why does the calculator assume the second time is later?
Because that is what people mean when they enter two times without dates: a shift, a flight, a stretch of sleep. Reading it forwards handles overnight spans correctly and never produces the negative number that betrays a simple subtraction. If you genuinely want the gap backwards, swap the two boxes — the answer is the twenty-four-hour complement of it.
How many hours is 9 to 5, really?
Eight, and with an unpaid lunch it is usually seven and a half — which is why the phrase is a description of office hours rather than a count of paid ones. Enter 9:00 am and 5:00 pm here and you get 8:00 exactly, in decimal 8.0; the hours calculator takes the break off, which is the number that matters on a form.
Can I get the answer in seconds?
It is there alongside the others. Seconds are the form that matters for video, audio and anything measured in frames — one second is 24, 25 or 30 frames depending on the format, so a duration in seconds converts straight into a frame count while one in hours and minutes does not.
Does this work across dates?
Only across one midnight — the calculator works on clock times, not calendar dates. That covers shifts, sleeps and flights within a day of each other, which is nearly everything people ask a duration calculator for. Multi-day spans are a date question rather than a time question and deserve a calendar tool.
How this works
Worked example
With From 9:00 am, To 5:30 pm, this page works out — h:mm. Given in hours and minutes, and in decimal hours — the two are not the same number.
Sources:
One duration, five forms
h:mm for reading and for checking against memory.
Decimal for payroll, invoices and anything with a rate attached.
Minutes and seconds for scheduling systems, video and audio, where hours are not the unit.