How to Calculate Area in the UK: Step-by-Step Guide

Updated · Maths

Introduction

Everyday maths comes up everywhere, from splitting a bill to checking a discount or helping with homework. A clear method makes it quick and reliable.

This guide explains how to calculate area in the UK, step by step. Work out the area of a rectangle or triangle in square metres and square feet. You'll see the formula, a fully worked example and practical tips for UK readers.

What this calculation covers

Work out the area of a rectangle or triangle in square metres and square feet.

Getting the method right means you can check prices, understand statistics in the news and help children with GCSE-style questions confidently.

The method and formula

Rectangle area = length × width. Triangle area = base × height ÷ 2. One square metre is 10.764 square feet.

Every figure on our area Calculator follows this method, so you can check the working yourself.

Worked example

Here's a typical example using these figures:

InputValue
ShapeRectangle
Length or base5 m
Width or height3 m

Running them through the method gives:

ResultValue
Area15 m²
In square feet161.46

The headline figure is area: 15 m². Change any input and the result will move with it.

How to use the calculator

  1. Enter or choose shape.
  2. Enter or choose length or base (m).
  3. Enter or choose width or height (m).
  4. Read your results. The main figure is shown at the top, with a breakdown underneath.
  5. Try different values to compare scenarios side by side.

Tips for UK readers

  • Write down which number is the 'whole' before working out any percentage.
  • Round only at the end of a calculation, not in the middle.
  • Check answers roughly in your head – does the result look sensible?
  • For statistics, note whether your data is a full population or a sample.

Frequently asked questions

What's the quickest way to work out area?

Use our free area Calculator. It applies this method automatically: Rectangle area = length × width. Triangle area = base × height ÷ 2. One square metre is 10.764 square feet.

Are these suitable for GCSE revision?

Yes. The methods match those taught in UK schools, and each page explains the formula used.

How many decimal places are shown?

Most results show up to two decimal places. Use the rounding in your working as your teacher or exam board requires.

Can I use negative numbers?

Yes, where they make sense mathematically, such as percentage change.

Summary

To work out area, follow the method above: Rectangle area = length × width. For a quick, accurate answer with your own figures, use the calculator.

Try the area Calculator

Enter your own figures and get an instant answer – free, no sign-up.

Open the area Calculator

Next, read Area: Common Mistakes, Tips and FAQs.

More maths guides

This guide is general information, not financial, tax, legal or medical advice. Figures use 2025/26 UK rates where relevant. Always check GOV.UK or NHS.uk for official guidance.