Work Hours Calculator

The calculator above does this automatically, but the arithmetic is worth understanding — mostly because it explains where manual timesheets go wrong.

Step 1 — convert to 24-hour time. 5:30pm becomes 17:30. Most timesheet errors start with an am/pm mistake.

Step 2 — convert both times to minutes. 09:00 is (9 × 60) = 540 minutes. 17:30 is (17 × 60) + 30 = 1,050 minutes.

Step 3 — subtract, then remove unpaid breaks. 1,050 − 540 = 510 minutes. Take off a 30-minute unpaid lunch and you have 480 minutes.

Step 4 — divide by 60 for decimal hours. 480 ÷ 60 = 8.00 hours. Payroll systems almost always want decimal hours rather than hours and minutes, which is the source of the next most common error.

For an overnight shift — clocking in at 22:00 and out at 06:00 — the end time is smaller than the start, so add 24 hours (1,440 minutes) to the end before subtracting. The calculator handles this automatically.

This trips people up constantly and quietly costs money in both directions. 7 hours 30 minutes is 7.5 decimal hours, not 7.30. Entering 7.30 into a payroll system underpays by 12 minutes; over a year across a team it is a meaningful sum, and it is the single most common manual timesheet error.

The conversion is minutes ÷ 60. Common values worth memorising:

• 15 minutes = 0.25 hours
• 20 minutes = 0.33 hours
• 30 minutes = 0.50 hours
• 40 minutes = 0.67 hours
• 45 minutes = 0.75 hours
• 50 minutes = 0.83 hours

The calculator shows both formats side by side so you can copy whichever your payroll system expects.

Overtime is where a generic hours calculator stops being useful, because the threshold and the multiplier are entirely jurisdiction-specific. The calculator applies the statutory default for each region below.

United States

The FLSA requires at least 1.5× the regular rate beyond 40 hours in a workweek. There is no federal daily overtime trigger — a 12-hour day followed by a short week carries no federal premium. States add their own rules: California applies 1.5× beyond 8 hours in a day and 2× beyond 12, which is why it is listed separately in the calculator.

India

Under the Factories Act, ordinary hours are 9 per day and 48 per week, with overtime at twice the ordinary rate — a considerably higher premium than most Western jurisdictions. Establishments outside the Factories Act fall under the relevant state Shops & Establishments Act, and thresholds, caps and overtime rates vary meaningfully between states, so confirm the rules for yours.

Australia

The National Employment Standards set 38 ordinary hours per week, but the overtime rate itself comes from the applicable modern award or enterprise agreement rather than the NES — commonly 1.5× for the first two or three hours and 2× thereafter. Award variation here is wide enough that the calculator's figure should be treated as a starting estimate only.

Singapore, UAE and the UK

Singapore's Employment Act provides 1.5× beyond 44 hours per week, but only for workmen earning up to S$4,500 and other employees up to S$2,600 per month, capped at 72 overtime hours monthly. The UAE sets 1.25× beyond 8 hours daily, rising to 1.5× for work between 10pm and 4am. The UK has no statutory overtime premium at all — any enhanced rate is contractual, though average working time is capped at 48 hours per week over a 17-week reference period unless the worker has opted out.

A calculator fixes the arithmetic. It does not fix the underlying data, and for a team the data is usually where the cost sits.

• Recall error. Timesheets completed on Friday for the whole week are reconstructions, not records. Research on retrospective time entry consistently finds substantial drift in both directions.
• Rounding drift. Everyone rounding to the nearest convenient quarter-hour sounds harmless and is systematically biased upward across a team.
• Unrecorded breaks. Unpaid breaks that were taken but never logged inflate paid hours invisibly.
• Missing overtime. Work performed off the clock is a wage-and-hour exposure under the FLSA specifically, and an accurate record protects the employer as much as the employee.
• Scope leakage. Hours landing on a client nobody is invoicing — invisible without task-level attribution.

This is the argument for automatic capture rather than better spreadsheets: the hours are recorded as they happen rather than remembered afterwards. Our guide to tracking employee hours accurately covers the transition, and moving from spreadsheets to time tracking covers the practical migration. For teams needing verified attendance rather than self-reported hours, attendance management and facial recognition attendance close that gap.