Time Duration: Your Questions Answered
These are the questions people ask most often about time duration. Each answer is short; follow the links for the full detail.
What does a time duration calculation tell me?
Calculates hours and minutes between two times, including overnight shifts.
What is the formula?
Duration = end − start (+24 h if end is earlier).
What do I need to enter?
Start time, End time.
Does this count Singapore public holidays?
No. It counts calendar days or weekdays. Subtract any public holidays in the period yourself.
Can you show an example?
For example, with these inputs:
- Start time: 09:00
- End time: 18:30
the calculator returns:
- Duration: 9 h 30 min
- In hours: 9.50 hours
Any tips?
- Notice periods in employment contracts may be counted in calendar days or working days, so read the wording carefully.
- Convert times to minutes before subtracting, then convert back to hours and minutes.
- Leap years add a 29 February every four years, except most century years.
Background
Age is calculated in completed years, months and days. Someone born on 29 February is usually treated as turning a year older on 28 February or 1 March in non-leap years, depending on the rule being applied.
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.
Singapore has 11 gazetted public holidays a year, and when one falls on a Sunday the following Monday is a holiday. Working-day calculations therefore need holidays removed separately from weekends.
Related calculations
- Age Calculator: Calculates exact age in years, months and days.
- Days Between Dates Calculator: Counts days between two dates.
- 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.
Try it yourself with the Time Duration Calculator.
Run your own numbers: Time Duration Calculator