Hours Worked: 5 Mistakes to Avoid
Totals a shift's paid hours after breaks. The maths is not complicated, but a handful of errors come up again and again in this and related date & time calculations. Here is what to watch for.
Many Singapore rules are expressed in days: notice periods, leave entitlements, stamp duty deadlines and probation periods. Whether the count includes the start or end date, and whether weekends count, changes the answer.
Time durations are easier to handle in minutes. Convert each time to minutes after midnight, subtract, then convert back to hours and minutes, adding 24 hours for shifts that run past midnight.
1. Assuming every month has 30 days
Month lengths vary from 28 to 31 days.
2. Forgetting public holidays
Working-day counts usually need holidays removed.
3. Ignoring leap years
29 February changes day counts in leap years.
4. Overnight time errors
If a shift ends after midnight, add 24 hours before subtracting.
5. Subtracting times in decimal
9:45 minus 8:30 is 1 h 15 min, not 1.15 hours.
The correct method
Hours = out − in − break.
For example, with these inputs:
- Clock in: 08:30
- Clock out: 17:45
- Unpaid break (minutes): 60
the calculator returns:
- Hours worked: 8 h 15 min
- Decimal hours: 8.25 hours
Related calculations
- Add Days to a Date Calculator: Finds the date a number of days after another date.
- Subtract Days from a Date Calculator: Finds the date a number of days before another date.
- Working Days Calculator: Counts weekdays between two dates, inclusive.
- Day of the Week Calculator: Tells you which weekday any date falls on.
The Hours Worked Calculator applies the formula consistently, so it is a quick way to double-check your own working.
Run your own numbers: Hours Worked Calculator