What scales do UK OS maps use?

The two main scales for walkers are 1:25,000 (OS Explorer, orange cover) where 4cm = 1km, and 1:50,000 (OS Landranger, pink cover) where 2cm = 1km. Explorer maps show more detail including field boundaries. Landranger maps cover a larger area per sheet.

How do I measure distance on a map?

Use a piece of string or the edge of your compass laid along the route, then measure against the map scale bar. For straight lines, a ruler works. For winding paths, a map measurer wheel is ideal. Remember map distance does not account for hills.

Does real distance account for hills?

No. Map distance is the horizontal (plan) distance. The actual walking distance on steep terrain is longer due to elevation changes. As a rough guide, add 10-15% to your distance estimate for hilly routes in the UK highlands.

CampCalcs

Map Scale Calculator

Convert map distances to real distances and vice versa for common UK Ordnance Survey map scales.

Conversion DirectionWhich way to convert

Map ScaleScale of your map

Map Distance

Distance measured on the map

Map UnitUnit of your map measurement

How We Calculate This

Conversion Formula

Real distance = Map distance x Scale factor

At 1:25,000, every 1mm on the map represents 25m on the ground. At 1:50,000, every 1mm represents 50m.

Quick Reference

1:25,000 — 4cm = 1km
1:50,000 — 2cm = 1km
1:10,000 — 10cm = 1km

Frequently Asked Questions

Related Calculators

Map Distance Calculator

Convert map measurements to real-world distances using your map scale.

Grid Reference Calculator

Convert between 6-figure and 8-figure OS grid references with easting and northing.

Bearing Calculator

Calculate the bearing between two grid references or coordinates.

Pace Counter Calculator

Calibrate your pace count for accurate distance measurement on foot.

Walking Time Calculator

Estimate walking time using Naismith's rule with Tranter's corrections for fitness.

Last updated: March 2026

All calculations are estimates. Always verify conditions and use proper safety equipment outdoors.