Scale drawings and maps

A scale drawing is an accurate picture of something much bigger or smaller, like a map or a house plan. The scale says how many real units each unit on the drawing stands for.

Key facts

  • Scale 1 : 50 means 1 cm on the plan is 50 cm in real life.
  • Real length = drawing length × scale.
  • Drawing length = real length ÷ scale.
  • Convert units at the end: 100 cm = 1 m, 100 000 cm = 1 km.

Worked examples

Example 1

On a 1 : 25 000 map, two villages are 8 cm apart. How far apart are they in km?

  1. 8 × 25000 = 200000 cm
  2. 200000 cm = 2000 m = 2 km

Answer: 2 km

Example 2

A room is 4.5 m long. How long is it on a 1 : 50 plan?

  1. 4.5 m = 450 cm
  2. 450 ÷ 50 = 9 cm

Answer: 9 cm