Geography
What is the scale on a map?
Quick answer
A map scale tells you how distances on the map compare with real distances. A scale of 1:50,000 means 1 cm on the map is 50,000 cm, or 500 m, on the ground.
In one sentence
Map scale is the rule that links a distance on the map to the real distance on the ground.
Explained
A map shrinks the real world to fit on paper. To know how far apart places really are, you need the scale. It is shown in three ways:
- As a ratio: 1:50,000. Every 1 unit on the map is 50,000 of the same unit on the ground. So 1 cm is 50,000 cm, which is 500 metres.
- As a statement: "1 cm to 5 km."
- As a scale bar (line scale): a little ruler printed on the map, marked with real distances.
map
ruler
globe
To find a real distance:
Step by step
- Measure on the map.Use a ruler, such as 4 cm.
- Multiply by the scale.If 1 cm is 5 km, then 4 cm is 4 × 5 = 20 km.
- Check the units.Convert if needed, for instance 200,000 cm = 2,000 m = 2 km.
To go the other way, divide. If a real distance is 6 km and the scale is 1 cm to 2 km, the map distance is 6 ÷ 2 = 3 cm. For a ratio like 1:50,000, a measurement of 4 cm gives 4 × 50,000 = 200,000 cm, which is 2 km. Handy conversions are in metric units, and the idea is a kind of ratio.
A road or river bends, so measure it with a piece of string, then lay the string straight along the ruler.
Maps come in different scales. A large-scale map, such as 1:10,000, shows a small area in a lot of detail (a town centre). A small-scale map, like 1:10,000,000, shows a big area with little detail (a continent). The word "large" sounds backwards, but remember: a large-scale map has a larger fraction. See maps and measuring length.
Examples
| Scale | 1 cm on the map is... | 4 cm is... |
|---|---|---|
| 1:10,000 | 100 m | 400 m |
| 1:50,000 | 500 m | 2 km |
| 1:100,000 | 1 km | 4 km |
| 1:1,000,000 | 10 km | 40 km |
Common mistakes
- Forgetting to change units. 1 km is 100,000 cm.
- Mixing up large and small scale. Large scale means more detail.
- Measuring a straight line on a winding road. Use string.
Quick quiz
Map scale
Check what you know with 4 quick questions.
Question 1 of 4
A map scale is 1 cm to 5 km. Two towns are 4 cm apart. How far apart are they?
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For grown-ups
Related topics
Maps
A map is a drawing of a place seen from above. A key explains its symbols, a scale shows real distances and a compass shows direction.
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Ratio
A ratio compares two or more amounts, written with a colon. A ratio of 2:3 means for every 2 of one thing there are 3 of the other.
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