Worked example 1
A train leaves at 13:48 and the journey is 2 h 25 min. When does it arrive?
- 13:48 + 2 h = 15:48.
- 15:48 + 12 min = 16:00.
- 25 − 12 = 13 minutes left, so 16:13.
Answer: 16:13
Everyday Adult Skills · Everyday
Working out time durations, 24-hour times and shift hours
Time durations answer questions like ‘How long is my train journey?’ or ‘How many hours did I work?’. Because there are 60 minutes in an hour, not 100, ordinary subtraction often gives the wrong answer.
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Before you start
Who it's for and what to know first
Reading clock times and knowing 60 minutes = 1 hour.
Learn it
How it works
- Count on in chunks rather than subtracting. From 09:15 to 10:40: 09:15 → 10:00 is 45 minutes, 10:00 → 10:40 is 40 minutes; total 85 minutes = 1 hour 25 minutes.
- 24-hour clock: afternoon and evening times add 12 to the hour. 3:20 pm = 15:20. 12:30 am = 00:30.
- Crossing midnight: count to 00:00 first, then add the rest. 22:30 → 00:00 is 1 h 30 min, then to 06:15 is 6 h 15 min; total 7 h 45 min.
- Adding a duration: add the hours, then the minutes, and carry every 60 minutes into an hour.
- For shift pay, subtract unpaid breaks from the total time.
Worked example 2
A shift runs 08:00–16:30 with a 30-minute unpaid break. How many paid hours?
- 08:00 → 16:30 = 8 h 30 min.
- Subtract 30 minutes.
Answer: 8 hours
Try it online · print it · check it
Practice questions
Tips
Common mistakes
- Subtracting times like ordinary numbers: 10:40 − 09:15 is not ‘1.25 hours’.
- Forgetting that 1 hour 30 minutes is 1.5 hours, not 1.3.
- Losing track when a time crosses midnight.
Last reviewed: 25 September 2026