Hours Calculator
Hours between two clock times, minus the break — the shift arithmetic every timesheet quietly runs.
Hours Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Single span per run — split shifts are two runs
- No rounding policy, no zones, no daylight handling
In short: Clock on at 09:00, off at 17:30, forty-five minutes of break: the shift is 7 hours 45 minutes — 7.75 in decimal, the number pay systems multiply by the rate. The break is the part people forget and the part the arithmetic refuses to: an unpaid break is not work, and half an hour a day is two whole weeks a year. When the clock-off time sits before the clock-on time, the shift crossed midnight and the arithmetic adds a day without being asked.
Formula
shift = (end − start mod 1440) − break
Both clock times convert to minutes past midnight; the difference is the span, and a negative difference means the shift crossed midnight, so a day (1,440 minutes) is added before the break comes off. The result in minutes divided by sixty is the decimal hours that payroll multiplies — seven three-quarters is not seven forty-five.
Worked Example
- Enter clock-on and clock-off in 24-hour time.
- Deduct the unpaid break in minutes.
- Read hours-and-minutes and decimal together.
Defaults: 09:00 to 17:30 minus 45 — 7 h 45 min, 7.75 decimal. Set the clock-off to 06:00 and the shift reads overnight: 20 h 15 min across the midnight.
Strengths & Limits Of This Model
Where this engine is strong
- Break deducted in the open, not in the small print
- Overnight detection built into the arithmetic
Where it stops
- One clock pair per run; no multi-break tally
Practical Use Cases
Timesheets
the daily figure before the week sums
Pay checks
decimal hours times the rate
Shift premiums
night hours identified honestly
Methodology & Editorial Standards
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Hours Calculator — 8 Expert FAQs
8 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
Why decimal hours on the same card?
Because payrolls multiply by a rate, and seven three-quarters of an hour is 7.75 while seven forty-five is a clock reading. Mixing the two up is the classic payslip dispute — both figures sit together so the conversion is never done in someone's head.
How does an overnight shift work?
When the clock-off reads earlier than the clock-on, the span went through midnight and a full day is added before the break. A 22:00 to 06:00 shift is eight hours, not negative fourteen — the arithmetic wraps once and says it did.
Should the break come off?
If it is unpaid, yes — that is what unpaid means. The half-hour lunch that quietly stays on the timesheet overstates a year's pay by about ten working days. Paid breaks simply enter zero and the span stands.
What about split shifts?
Run each leg through the page and add the results, or read the duration page to add them as raw spans. A single pair of clock times can only describe one span; honesty beats pretending.
Does the break cap at the shift length?
It must — a break longer than the span is a contradiction, and the panel refuses it rather than printing negative work. Check which day the break belongs to on a night shift; the arithmetic assumes it falls inside the span.
Where do time zones sit?
Nowhere, deliberately. A shift in one zone is modulo arithmetic; a shift that crosses a zone or a daylight switch changes the wall clock under your feet, and that belongs on a map with the actual rules, not on this panel.
Why 24-hour input?
It removes the a.m./p.m. guess that produces phantom afternoon shifts. 06:00 is six in the morning without a qualifier; the clock-off preset at 06:00 is the night-shift exit.
Is rounding applied?
None — the minutes are exact. Timesheet systems round to quarters or tenths by their own rules; the honest raw figure comes first, the rounding policy belongs to the employer and the payslip.