Which calculator should I use?
The tools overlap a little on purpose — here’s the quickest way to the right one.
| If you want to… | Use |
|---|---|
| Find hours worked in a shift, with breaks and decimal hours | Hours Calculator |
| Find the plain gap between two date-times, even across days | Time Duration Calculator |
| Total a whole week of shifts at once | Time Card Calculator |
| Add or subtract hours and minutes from a time | Add & Subtract Time |
| Find what time it was, or will be, a set duration away | Time Ago / Time From Now |
| Turn 8:30 into 8.50 decimal hours for payroll | Time to Decimal |
| Count working days between two dates | Business Days Calculator |
| Plan a bedtime around sleep cycles | Sleep Calculator |
Built for real timesheets, not just tidy numbers
Most time-calculation mistakes aren’t maths errors — they’re the messy edges: a shift that runs past midnight, an unpaid lunch nobody subtracted, or 8 hours 30 minutes typed into payroll as 8.30 instead of 8.50. These calculators are built around exactly those edges. Overnight spans are detected automatically, breaks are handled explicitly, and decimal hours are shown wherever payroll needs them.
Need to convert a time’s format rather than calculate with it? See the time format converters for 24-hour, 12-hour, and military time, or jump straight to the 24 to 12 hour converter on the home page.
Frequently asked questions
What’s the difference between the hours calculator and the time duration calculator?
The hours calculator is built around payroll, with a break field and decimal hours as the headline. The time duration calculator gives the plain gap between two date-times and supports spans of several days.
Which tool converts time to decimal hours for payroll?
Use Time to Decimal for the conversion on its own, or the hours calculator, which shows decimal hours alongside the total.
Do these calculators handle overnight shifts?
Yes. The hours and duration calculators detect when a span crosses midnight and add the extra day automatically, and flag it so the adjustment is visible.
Are the calculators free to use?
Yes. Every calculator is free, needs no sign-up, and runs entirely in your browser — nothing you enter is uploaded or stored.
Explore other categories
Every calculator here is built and reviewed by Fletcher Langley, with the method shown on each tool and examples verified by hand — see our editorial policy. These tools are planning and verification aids, not a substitute for your own payroll or scheduling system.