⏰ Time

Master clocks, durations, timetables and time calculations!

📖 Learn
12hr, 24hr & durations

✏️ Examples
Worked problems

🔬 Visualiser
Interactive clock tools

🎯 Practice
20 mixed questions

📖 Time

1. 12-Hour and 24-Hour Clocks

There are two ways to write time. The 12-hour clock uses AM (midnight to noon) and PM (noon to midnight). The 24-hour clock runs from 00:00 (midnight) to 23:59.

12:00 AM = midnight = 00:00 | 12:00 PM = noon = 12:00

12-Hour	24-Hour	Note
12:00 AM (midnight)	00:00	Start of day
1:00 AM	01:00	Early morning
12:00 PM (noon)	12:00	Midday
1:00 PM	13:00	Afternoon
11:59 PM	23:59	Last minute of day

2. Converting Between 12-Hour and 24-Hour

12-hour → 24-hour:

AM times: keep the same (but write 1:00 AM as 01:00)
12:00 AM → 00:00 (special case)
PM times: add 12 (except 12 PM stays as 12:00)

PM time → 24-hour: add 12 to the hour
e.g. 3:45 PM → 3 + 12 = 15 → 15:45

24-hour → 12-hour: if hour ≥ 13, subtract 12 and add PM. If hour = 0, write 12:xx AM.

3. Time Intervals and Durations

A duration is how long something takes. To find it, subtract the start time from the end time.

Duration = End Time − Start Time
End Time = Start Time + Duration

Bridging through hours: Count up in steps. From 09:40 to 11:10 → 9:40 to 10:00 = 20 min, 10:00 to 11:10 = 70 min → total = 90 min.

4. Adding and Subtracting Time

Time uses base-60 for minutes and base-24 for hours. You can't just add like regular numbers!

60 minutes = 1 hour | 24 hours = 1 day

Cross midnight example: Departs 22:30, arrives 06:15.
22:30 → 00:00 = 1h 30m. 00:00 → 06:15 = 6h 15m. Total = 7h 45m = 465 minutes.

Adding time: Add hours, then minutes. If minutes ≥ 60, carry 1 hour.

5. Reading Timetables

Timetables show times in 24-hour format. Each column is usually a different service (bus/train), each row is a stop.

Stop	Service A	Service B	Service C
Town Centre	08:00	09:15	10:30
Park Road	08:22	09:37	10:52
Station	08:45	10:00	11:15

Journey time: Station arrival − Town Centre departure = 08:45 − 08:00 = 45 minutes for Service A.

✏️ Worked Examples

Example 1 – Converting 12-hour to 24-hour

Convert 3:45 PM to 24-hour time.

It is PM, so add 12 to the hour: 3 + 12 = 15

Keep the minutes: 45

Answer: 15:45

Example 2 – Finding a Duration

A train departs at 09:20 and arrives at 11:45. How long is the journey?

From 09:20 → 10:00 = 40 minutes

From 10:00 → 11:45 = 1 hour 45 minutes = 105 minutes

Total = 40 + 105 = 145 minutes (2 hours 25 minutes)

Example 3 – Finding an End Time

A film starts at 14:30 and lasts 1 hour 45 minutes. When does it finish?

14:30 + 1 hour = 15:30

15:30 + 45 minutes = 16:15

Answer: 16:15

Example 4 – Crossing Midnight

An overnight coach departs at 22:45 and arrives at 05:30 the next day. How long is the journey in minutes?

22:45 → 00:00 = 1h 15m = 75 minutes

00:00 → 05:30 = 5h 30m = 330 minutes

Total = 75 + 330 = 405 minutes

🔬 Time Visualiser

Clock Converter

Enter a 12-hour time to see its 24-hour equivalent.

Hour (1–12):

Minute (0–59):

Duration Calculator

Find the duration between two 24-hour times.

Start hour (0–23):

Start minute:

End hour (0–23):

End minute:

End Time Finder

Enter a start time and duration to find the end time.

Start hour (0–23):

Start minute:

Add hours:

Add minutes:

Exercise 1 – 12-Hour to 24-Hour

Convert each 12-hour time to 24-hour format. Write as a 4-digit number (e.g. 08:30 = 830, 15:45 = 1545). Midnight = 0.

Exercise 2 – Time Durations (in minutes)

Calculate the duration in minutes between each pair of times.

Exercise 3 – Finding End Times

Work out the end time in 24-hour format (answer as HHMM, e.g. 10:30 = 1030).

Exercise 4 – Finding Start Times

Work out the start time in 24-hour format (answer as HHMM, e.g. 09:00 = 900).

Exercise 5 – Word Problems

Read each problem carefully. Give times as HHMM (24-hour) or durations as minutes.

🎯 Practice – 20 Questions

Mixed time questions. Give times as HHMM or durations as minutes.

🏆 Challenge

Harder time problems. Give times as HHMM or durations as minutes.