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Map Scale Calculator

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

Which way to convert

Scale of your map

Distance measured on the map

Unit 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

Last updated: March 2026

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