Hours Calculator

A timesheet that adds up the way payroll expects, in your browser.

Free, no limit Nothing uploaded No sign-up Works on mobile
Day Start End Break, minutes Worked

A timesheet that adds up the way payroll expects

Working out hours from a timesheet is simple arithmetic that goes wrong in three particular places, and all three cost somebody money.

The first is midnight. A shift from ten at night until six in the morning is eight hours, and a calculator that subtracts one time from the other gets minus sixteen. This one knows that an end time before a start time means the shift crossed into the next day.

The second is decimal hours. Payroll wants 7.75, not 7:45, and the two look similar enough that people type one where the other belongs. Both are shown here, side by side, every time.

The third is rounding, and it is the one nobody notices. Round each day to the nearest quarter hour and then add, and you get a different answer from adding first and rounding once. Over a five day week it can cost half an hour, and never in the worker's favour. This rounds the total.

A weekly timesheet being added up into total hours
How it works

Type, and read the answer

There is no button to press and nothing to wait for. The sum runs as you type.

1

Fill it in

Times can be written any way you like: 9, 09:00, 0900 or 9am all mean the same thing.

2

Read both forms

Hours and minutes for a person, decimal hours for a payroll system or an invoice.

3

Check the working

Every row shows its own total, so a figure that looks wrong can be traced to the day it came from.

How the sum is done

Each row becomes a number of seconds: the end time minus the start time, plus twenty four hours if the end came first, minus the break. Seconds rather than hours because a quarter of an hour is not a round number in decimal and errors accumulate when it is treated as one.

Times are read loosely on purpose. Somebody filling in a week of shifts on a phone will write 9, 0900, 9am and 09:00 in the same column, and refusing three of the four would be a tool that makes its user do the tidying. A bare number in the break column means minutes, because a thirty hour lunch is not what anyone meant.

The total is then rounded, once, if you asked for rounding. Everything is displayed twice: as hours and minutes for a human, and as decimal hours for a payroll system. Neither is more correct; they are the same number for two different readers.

Minutes as decimal hours

MinutesDecimalMinutesDecimal
50.08350.58
100.17400.67
150.25450.75
200.33500.83
250.42550.92
300.50601.00

The four in the middle are the ones worth learning, because they come up constantly: a quarter hour is 0.25, a half is 0.50, three quarters is 0.75, and a whole hour is 1.00. Everything else is a division by sixty.

The trap is that 45 minutes looks like it should be 0.45. It is 0.75. Writing 7.45 on a timesheet when you worked 7 hours 45 minutes gives away eighteen minutes a day, which is a day and a half over a year.

Four weeks worked out

A standard week

Nine to half past five, Monday to Friday, with a thirty minute break each day. Each day is eight and a half hours less half an hour, so eight hours. Five of those is 40:00, or 40.00 decimal. The number everyone expects, and the one that makes the other three look surprising.

A week of night shifts

Ten at night until half past six in the morning, with a thirty minute break, five nights. The end time is earlier than the start time on every row, which is the case most calculators get wrong. Each night is eight and a half hours less the break, so eight hours, and the week is 40:00 again. The clock going past midnight changes nothing about how long you were there.

A week of ragged shifts

Retail hours: 07:45 to 13:10, 12:00 to 20:20, 09:30 to 14:05, 14:00 to 22:35, 08:15 to 16:40, with no breaks recorded. That comes to 5:25, 8:20, 4:35, 8:35 and 8:25, which is 35:20 in total, or 35.33 decimal hours. Nothing here is a round number, which is exactly why it is worth having the sum done rather than estimated.

The same week, rounded two ways

Take five days of 7:52. Rounding the total to the nearest quarter hour gives 39:20 rounded to 39:15. Rounding each day first gives 7:45 five times, which is 38:45. The two methods differ by half an hour, and the daily one is smaller. Over a year of fortnightly pay that is thirteen hours.

Neither method is dishonest and both are used. It is simply worth knowing which one your employer applies, because it is the difference between two numbers that are both described as your hours.

How to fill it in

  • Times can be written any way you like. 9, 9:00, 09:00, 0900, 9am and 9 AM all mean nine in the morning. 17:30 and 5:30pm are the same evening.
  • The break box is a length, not a clock time. A bare number means minutes, so 30 is half an hour. 1:15, 1h 15 and 75m all work too.
  • Leave a day blank and it is skipped. Add rows for a fortnight, or use five for a normal week.
  • Overnight shifts need nothing special. Put in 22:00 and 06:00 and the answer is eight hours.
  • An hourly rate is optional, and if you give one the pay is worked out from the rounded total.

Why decimal hours exist at all

Because you cannot multiply 7:45 by a rate. Payroll systems store time as a decimal number of hours so the arithmetic works: 7 hours 45 minutes is 7.75 hours, because 45 minutes is three quarters of one. The mistake is writing 7.45, which is 7 hours and 27 minutes, and is 18 minutes a day less than you worked.

Nothing you type leaves the page

A timesheet says where somebody was and for how long. A duration between two dates is often a contract, a notice period or a medical appointment. Neither is anybody else's business, and neither is sent anywhere.

The whole calculation is a few lines of arithmetic running in your browser as you type. There is no request to a server, no account, nothing stored and nothing to delete afterwards. Disconnect from the internet once the page has loaded and it carries on working, which is the simplest demonstration there is.

That is not a special measure taken for this page. It is how every tool on this site works, because the alternative is asking people to hand over something private in exchange for arithmetic they could have done on paper.

How this compares with the alternatives

A spreadsheet

The right answer if you do this every week, and worth the twenty minutes it takes to build. It will also happily return minus sixteen hours for a night shift unless you write the formula that handles midnight, which is the part people forget.

Doing it on paper

Fine for one day and unreliable for five, because the decimal conversion has to be done by hand each time and 45 minutes is not 0.45.

Payroll software

What your employer uses, and it will be right. This page is for checking it, which is a reasonable thing to want to do and difficult without a second calculation to compare against.

A phone calculator

Works, if you convert everything to minutes first and back at the end. That conversion is exactly where the mistakes happen.

If the answer looks wrong

A day says time?

One of the two times could not be read. Almost anything sensible works, but a stray letter or a missing digit will not. Try 09:00 and 17:30 in that row and it will clear.

A day says break?

The break box takes a length rather than a clock time. Write 30 for half an hour, or 1:15, or 90m. A time of day such as 13:00 is not a break of any length.

The night shift shows a full day

Check the two times are not identical. 22:00 to 22:00 is read as zero rather than as twenty four hours, because a zero length shift is far more likely to be a typing mistake than a genuine round the clock stint.

The total does not match my payslip

Look at the rounding first. Many employers round each day rather than the week, which usually produces a smaller number. Set the rounding to match theirs and see whether the gap closes; if it does, that is the difference and it is worth asking about.

The pay figure looks off by a few pence

It is worked out from the rounded total, not from each day, and it is not rounded to the nearest penny until the end. Payroll may do both differently.

Free, with no account and no limit

No sign-up, no daily cap, nothing held back behind a paid tier. The calculation costs us nothing because it happens on your device.

If you need the other direction, converting a number of hours into minutes or days into hours, our hours and minutes converter and days to hours converter do exactly that, with charts and the formula shown.

And if what you are really doing is working out a percentage of a total, or a percentage increase, the percentage calculator shows every step of the working rather than just the answer.

FAQ

Hours Calculator

The questions people ask most about this calculation.

Put the start and end times in, and the break in minutes. Each row shows that day in both hours and minutes and in decimal hours, and the total is at the bottom.

Yes. An end time earlier than the start time is taken as the next morning, so 22:00 to 06:00 is eight hours.

They are the same length written two ways. 45 minutes is three quarters of an hour, so 7 hours 45 minutes is 7.75 decimal hours. Writing 7.45 instead is a common and expensive mistake.

Because rounding each day and then adding loses time. Five days of 7:52 is 39:20, which rounds to 39:15. Rounded daily first it would come to 38:45, half an hour less, and that is your half hour.

As a length. A plain number is minutes, so 30 means a half hour break. You can also write 1:15, 1h 15 or 90m.

No. The whole calculation happens in your browser as you type. Nothing is transmitted and nothing is stored.

Completely, with no sign-up, no limit and nothing held back. The arithmetic runs on your device and costs us nothing to provide.

No. The page you are on is the whole thing, and it works the same on Windows, macOS, Android and iPhone.

Yes. The fields accept the way people type on a phone, including 0900 and 9am, and the number pad comes up for the time boxes.

No. Nothing is transmitted and nothing is saved. Reload the page and it is empty again.

Yes. A time card calculator and a time clock calculator all describe this page. The names differ because people describe the same job differently; the job itself does not change.
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