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# Time difference calculations
- URL: https://www.esheets.io/time-difference-calculations/
- Published: 2025-05-02T17:59:10.000Z
- Updated: 2026-06-21T16:47:18.000Z
- Author: Richard Linnington
- Tags: Maths, Number

Working out the time difference between two times is a key skill for everyday life — from figuring out how long a journey takes, to knowing how much time you have left before a deadline. It's all about keeping track of time accurately and planning ahead with confidence! [Jump to the questions](#practise-now)

## Practise now

Worksheet preview and key skills 

### Worksheet preview

Practise time difference calculations with this self-marking maths worksheet.

The interactive worksheet below generates questions, gives instant feedback, and lets students record their score.

#### What you’ll practise

- Counting forwards or backwards between two times.
- Working across hours, days or midnight where needed.
- Converting between hours and minutes.
- Writing time differences using appropriate units.

Use the interactive worksheet below, or read the [Topic guide](#topic-guide) for the method and worked example.

## Topic guide

### What this worksheet practises

This worksheet provides practice on calculating the exact difference between two times on a 12-hour or 24-hour clock. The most important thing to remember is that time operates in blocks of 60, not 100, so you cannot use normal column subtraction for difficult times.

### Key method

The most foolproof method is the "Number Line" or "Stepping" method.

- Write down your Start Time on the left and your End Time on the right.
- **Step 1 (Minutes to the hour):** Jump from your Start Time to the very next "full hour". Note down how many minutes this took.
- **Step 2 (The full hours):** Jump from this new full hour across to the full hour closest to your End Time. Note down how many hours this took.
- **Step 3 (The remaining minutes):** Jump from this final full hour to your exact End Time. Note down the minutes.
- Add all your jumps together to get the total time difference.

### Worked example

**A train departs at 08:45 and arrives at 11:20\. How long was the journey?**

Start: 08:45\. End: 11:20.

Step 1: Jump to the next full hour (09:00).

From 08:45 to 09:00 is **15 minutes**.

Step 2: Jump the full hours to get close to the end (from 09:00 to 11:00).

From 09:00 to 11:00 is **2 hours**.

Step 3: Jump the remaining minutes (from 11:00 to 11:20).

From 11:00 to 11:20 is **20 minutes**.

Step 4: Add them all together.

2 hours + 15 mins + 20 mins = **2 hours and 35 minutes**.

### Common mistakes to avoid

The most catastrophic mistake is trying to use standard column subtraction on times. For example, 11:20 − 08:45\. A student might try to "borrow" from the hours column, treating it like a normal 100s column, resulting in nonsensical answers. Never use column methods for time differences if the minutes cross over an hour boundary. Always use the stepping method.

### Things to remember

If you have to do a calculation that crosses midnight (e.g. a flight from 22:30 to 04:15), the stepping method is even more vital. Jump from 22:30 to midnight first (1 hr 30 mins), and then jump from midnight to the end time (4 hr 15 mins), then add them together.