How do I work out the hours between two times, like 9:00 to 17:30?

Pick the Between mode, type 09:00 as the start and 17:30 as the end, and the tool reads 8 h 30 m, with the decimal-hour value 8.5 shown next to it. It subtracts start from end in minutes (1050 − 540 = 510 minutes), then splits that into hours and minutes. If the end is earlier than the start on the clock and you are doing a normal daytime span, double-check the values; if it is a night shift, flip the overnight switch.

How does it handle an overnight or graveyard shift across midnight?

Tick the overnight box. Without it, 23:00 to 01:00 would look like a negative span, because 01:00 is a smaller clock number than 23:00. With overnight on, the end time is treated as the next day, so the tool adds 24 hours to it: 23:00 to 01:00 becomes 2 hours, and 22:30 to 06:15 becomes 7 h 45 m. This is exactly how a night-shift timesheet should count the hours worked past midnight.

How do I convert a duration like 8 h 30 m into decimal hours?

Divide the minutes by 60 and add to the hours: 30 minutes ÷ 60 = 0.5, so 8 h 30 m = 8.5 hours. The tool shows the decimal value automatically in every mode. Common ones to memorise: 15 min = 0.25 h, 20 min = 0.33 h, 45 min = 0.75 h. Payroll systems almost always want decimal hours, not HH:MM, which is why a row reading 7 h 45 m is paid as 7.75 hours.

How do I add up a whole week of work hours?

Use the Timesheet mode and add one row per day or per session: 08:00, 07:30, 08:15, and so on as HH:MM durations (not clock times). The tool sums them into a total like 38 h 45 m and shows the decimal total 38.75. Add your hourly rate and it multiplies the decimal hours by the rate for gross pay. If a day had a split shift, just add two rows for that day.

When figuring pay, should I use decimal hours or HH:MM?

Use decimal hours for any multiplication by a rate. You cannot multiply 7 h 45 m by 20 directly and get the right answer — you would get 140 of something meaningless. Convert first: 7 h 45 m = 7.75 hours, then 7.75 × 20 = 155. The Timesheet mode does this for you: it keeps the readable HH:MM total for the timecard and the decimal total for the payroll line, side by side.

Count a night-shift worker's hours across midnight

A nurse clocks in at 22:30 and out at 06:45 the next morning. Put it in Between mode, switch on overnight, and read 8 h 15 m (8.25 hours) without subtracting 24 in your head or guessing the sign. Do it for each shift on the schedule and the payroll line writes itself — no more "is that nine hours or seven?" arguments at the end of the pay period.

Total a fortnight of variable shifts for payroll

Retail and hospitality rotas rarely run a flat eight hours. Drop each worked block into Timesheet mode — 6 h 30 m Monday, 9 h 15 m Tuesday, a 4-hour Saturday — and the tool sums them to a clean total with the decimal hours ready to paste into the payroll sheet. Add the hourly rate and you have gross pay before deductions in one read.

Find when a deadline lands after adding lead time

A batch process starts at 14:20 and the documented runtime is 6 hours 50 minutes. Add/Subtract mode gives you 21:10, same day. Bump the runtime and it tells you the moment it spills past midnight with a +1 day badge, so you know whether to warn the overnight on-call before you go home.

Check a meeting or appointment length quickly

Someone proposes 13:45 to 15:30. Between mode says 1 h 45 m. Useful for double-booking checks, billing a client by the quarter-hour, or confirming a 90-minute slot is actually 90 minutes and not an optimistic 75. Share the URL and the other person sees the exact same times and result.

Time Duration Calculator — Hours Between Times, Add Time, Timesheet

Hours between two times, add or subtract time, and add up a timesheet — decimal hours + pay — browser-only

Runs locally
Category Calculator
Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.

Clock arithmetic in three modes. Between: hours between a start and end time (tick overnight for shifts past midnight). Add/Subtract: shift a base time by hours and minutes. Timesheet: add up HH:MM durations and a rate for pay. Decimal hours shown everywhere — that is what payroll wants.

Start timeEnd time

Crosses midnight (overnight)— End is on the next day, e.g. 23:00 → 01:00 = 2h

Duration

8h 30m

Decimal hours: 8.5 h

What this tool does

A time duration calculator for the everyday clock math nobody enjoys doing by hand. Three modes in one tool. Between two times: enter a start and end on a 24-hour clock and read the gap as "8 h 30 m" plus decimal hours (8.5), with an overnight toggle for shifts that cross midnight so 23:00 to 07:00 comes out as 8 hours, not minus sixteen. Add or subtract time: take a base time, add or take away hours and minutes, and get the resulting clock time with a +1 day or -1 day badge when it rolls over. Timesheet: stack as many HH:MM durations as you worked, total them, see the decimal-hour sum, and multiply by an hourly rate to get gross pay. Unlike a unit converter (which just turns minutes into hours) or a date difference tool (which counts whole days), this one does clock arithmetic — what time is it after, how long between, how many hours this week. Every keystroke stays in your browser, the link is shareable, copy is one click. 100% client-side, nothing uploaded.

Tool details

Input: Numbers; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 9 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Calculator · Operations; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How Time Duration Calculator fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

Getting a realistic range before a purchase, plan, workout, or schedule decision.
Comparing scenarios by changing one input at a time.
Turning rough assumptions into a number you can discuss.

Calculation checks

Double-check units, dates, rates, and rounding assumptions.
Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Count a night-shift worker's hours across midnight
A nurse clocks in at 22:30 and out at 06:45 the next morning. Put it in Between mode, switch on overnight, and read 8 h 15 m (8.25 hours) without subtracting 24 in your head or guessing the sign. Do it for each shift on the schedule and the payroll line writes itself — no more "is that nine hours or seven?" arguments at the end of the pay period.
Total a fortnight of variable shifts for payroll
Retail and hospitality rotas rarely run a flat eight hours. Drop each worked block into Timesheet mode — 6 h 30 m Monday, 9 h 15 m Tuesday, a 4-hour Saturday — and the tool sums them to a clean total with the decimal hours ready to paste into the payroll sheet. Add the hourly rate and you have gross pay before deductions in one read.
Find when a deadline lands after adding lead time
A batch process starts at 14:20 and the documented runtime is 6 hours 50 minutes. Add/Subtract mode gives you 21:10, same day. Bump the runtime and it tells you the moment it spills past midnight with a +1 day badge, so you know whether to warn the overnight on-call before you go home.
Check a meeting or appointment length quickly
Someone proposes 13:45 to 15:30. Between mode says 1 h 45 m. Useful for double-booking checks, billing a client by the quarter-hour, or confirming a 90-minute slot is actually 90 minutes and not an optimistic 75. Share the URL and the other person sees the exact same times and result.

Common pitfalls

Forgetting the overnight toggle on a shift that crosses midnight. Without it the tool sees the end time as earlier than the start and the span goes negative or wrong. If a shift ends "tomorrow", flip overnight on so the end is read as the next day.
Multiplying an HH:MM time by an hourly rate. 7 h 45 m × 20 is not a valid calculation — you must convert to 7.75 decimal hours first. Always pay off the decimal-hour figure the tool shows, never the HH:MM string.
Typing clock times into the Timesheet rows. Timesheet adds up durations (how long each block was), not points on the clock. Enter 08:00 meaning eight hours, not the moment 8 a.m. To go from clock-in/clock-out to a duration, use Between mode first.

Privacy

Every calculation — the minute subtraction, the overnight roll-over, the decimal conversion and the pay multiply — is plain JavaScript that runs in your browser tab. No time, shift or pay figure is sent anywhere and nothing is logged. The one caveat: the shareable URL encodes your inputs in the query string, so a link pasted into chat records those times in the recipient server's access log. For a confidential payroll figure, use the copy button and paste the text rather than sharing the URL.

FAQ

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Time Duration Calculator — Hours Between Times, Add Time, Timesheet

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How Time Duration Calculator fits into your work

Calculation jobs

Calculation checks

Good next steps

Real-world use cases

Count a night-shift worker's hours across midnight

Total a fortnight of variable shifts for payroll

Find when a deadline lands after adding lead time

Check a meeting or appointment length quickly

Common pitfalls

Privacy

FAQ

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