Two jobs, one calculator
Clocked in at 9:00 and out at 5:30. How long was that, really? Eight and a half hours, sure, but your timesheet wants it as a number and your brain just stalled on the “30 minutes is point-five” part. Feed it two clock times and it spits back the gap in hours and minutes, total minutes, and decimal hours all at once.
The second mode runs the other way. Give it a start time, tell it to add or subtract hours and minutes, and it tells you the time you land on.
Time between two clocks
Pick a start and an end. The result updates as you type, no submit button. You get three numbers because different forms want different things:
- Hours and minutes (like 8h 30m) for anything human-readable
- Total minutes for systems that only take minutes, or when you’re summing lots of short intervals
- Decimal hours (8.50) for payroll, invoices, and spreadsheets
What about a shift that runs past midnight? Leave the day offset on “same day” and flip the auto +1 day toggle. Now an end time of 02:00 against a start of 22:00 reads as 4 hours, not minus 20. Working a really long block across two or three calendar days? Use the offset picker instead and add the extra days yourself.
Add or subtract from a time
This side is for “what time will it be” questions. Set the start, choose add or subtract, type the hours and minutes, and read the answer.
Say a recipe needs a 90-minute rest and you want it ready by 7:00 pm. Subtract 1 hour 30 minutes from 19:00 and you get 17:30. Start the dough at half past five. The same trick handles “my flight boards in 3 hours 20 minutes” or “the parking meter runs out 2 hours from now.” When the math pushes past midnight or before it, you’ll see a little “next day” or “previous day” note under the result so you don’t get caught out.
Decimal hours, explained
Payroll almost never wants “8 hours and 15 minutes.” It wants 8.25. The conversion trips people up because minutes are base 60 and decimals are base 100, so 15 minutes is not 0.15. It’s a quarter of an hour, which is 0.25.
A few you’ll memorize fast:
- 15 min = 0.25
- 30 min = 0.50
- 45 min = 0.75
- 20 min = 0.33 (close enough for most timesheets)
- 1h 30m = 1.50
The formula is just minutes divided by 60. The calculator does it for you and rounds to two places, so when you multiply by an hourly rate the dollars come out right.
Where this gets used
Shift workers reconcile clock-in and clock-out times that cross midnight. Contractors log billable blocks and need the decimal version for an invoice. Managers sanity-check a timesheet before approving payroll. Cooks and bakers work backwards from a serving time. It’s all plain arithmetic on minutes, so it’s instant, works offline once the page loads, and your times never leave the browser.
Common questions
How do I handle a shift that ends after midnight?
Keep the day offset on “same day” and leave auto +1 day on. The tool sees the end time is earlier than the start and adds a day for you. For spans longer than 24 hours, use the day-offset dropdown.
Why does 30 minutes show as 0.50 and not 0.30?
Because decimal hours are fractions of an hour, not minute counts. Thirty minutes is half an hour, so it’s 0.50. Divide any minute value by 60 to get the decimal.
Can it add more than 24 hours?
Yep. In add/subtract mode, put a big number in the hours box. The result wraps around the clock and the “next day” label tells you how many days forward you landed.
Does it round seconds?
No, the tool works in whole minutes only. If your time tracker logs seconds, round them off first or treat them as a separate column.
Is my data sent to a server?
Nope. Everything is calculated in your browser with simple math. Nothing gets uploaded, logged, or stored.
What if I just want the gap as a single number of minutes?
The “total minutes” box gives you exactly that. Handy when you’re adding up a stack of short breaks or comparing intervals that are all under an hour.