What does a 1:50,000 map scale mean?

A 1:50,000 scale means 1 unit on the map equals 50,000 of the same unit in the real world. So 1 cm on the map = 50,000 cm = 500 m in reality.

How do I measure distance on a paper map?

Use a ruler to measure the straight-line distance between two points. For curved routes like roads or rivers, use a piece of string or a map measurer wheel, then measure that length against the ruler.

What scale are topographic maps?

Common topographic scales are 1:25,000 (detailed hiking maps) and 1:50,000 (regional hiking/military maps). City maps typically range from 1:10,000 to 1:20,000, while road atlases use 1:250,000 or smaller.

Can I use this for imperial units?

Yes. You can enter the map measurement in inches and the result appears in feet, yards, and miles alongside the metric equivalents.

How far is 1 inch on a 1:24,000 map?

On a USGS 7.5-minute topographic map at 1:24,000, 1 inch equals 24,000 inches, which is 2,000 feet or about 0.38 mile (610 m). One mile on the ground is 2.64 inches on the map, and 1 cm on the map is 240 m.

How do I find the scale of a map?

Measure the map distance between two points whose real distance you know, convert both to the same unit, and divide: N = real distance ÷ map distance. If two towns 12 km apart are 4.8 cm apart on the map, N = 1,200,000 cm ÷ 4.8 cm = 250,000, so the scale is 1:250,000. Use the Find Scale mode to do this.

How do I convert a verbal scale like 1 inch = 1 mile to a ratio?

Express the ground distance in the map unit. One mile is 63,360 inches, so 1 inch = 1 mile is 1:63,360. Likewise 1 inch = 2,000 feet is 1:24,000 and 1 cm = 1 km is 1:100,000. Enter the verbal scale in the calculator and it fills in the ratio.

Is the straight-line distance on a map the same as the real distance?

Only on large-scale maps over short distances. Over long distances the shortest path is a great circle on the curved Earth, and a ruler on a flat projection can be off by several percent. For two latitude/longitude points use the coordinate card, which uses Vincenty's formula on the WGS84 ellipsoid (with the haversine sphere value for comparison).

What is the reverse calculation?

Reverse mode lets you enter a real-world distance and get back the corresponding map distance. This is useful when you want to mark a specific distance on a map or check if a route fits within a certain area of the sheet.

Map Distance Calculator

Enter a map measurement and scale to get the real-world distance, work backwards to map length, find an unknown scale, or measure the great-circle distance between two latitude/longitude points.

Map Scale & Distance

Scale Preset

Scale Ratio (1 : N)

1 :

Or verbal scale

1 =

Direction

Map Distance

Results

Real-world distance for 1 cm on a 1:50,000 map:

Meters

500

Kilometers

0.5

Feet

1,640.4

Miles

0.311

Yards

546.8

Nautical Miles

0.270

Common benchmarks at current scale

Distance Between Two Coordinates

Decimal degrees; south latitudes and west longitudes are negative.

Point A latitude

Point A longitude

Point B latitude

Point B longitude

Kilometers

—

Miles

—

Nautical miles

—

Initial bearing

—

Ellipsoidal (Vincenty, WGS84) distance; the spherical haversine value is shown for comparison.

Map Scale Conversion Table

Scale	1 cm =	1 inch =	1 km on map	1 mile on map	Typical use
1:10,000	100 m	833 ft	10 cm	6.336 in	City plan, cadastral
1:24,000	240 m	2,000 ft	4.167 cm	2.64 in	USGS 7.5′ topo quad
1:25,000	250 m	2,083 ft	4 cm	2.534 in	Hiking (OS Explorer, IGN)
1:50,000	500 m	4,167 ft	2 cm	1.267 in	Regional hiking, military
1:62,500	625 m	5,208 ft	1.6 cm	1.014 in	Old USGS 15′ quad
1:63,360	634 m	1 mi	1.578 cm	1 in	1 inch to the mile
1:100,000	1 km	1.58 mi	1 cm	0.634 in	USGS 30′ × 60′, regional
1:250,000	2.5 km	3.95 mi	0.4 cm	0.253 in	Road atlas, USGS 1° × 2°
1:500,000	5 km	7.89 mi	0.2 cm	0.127 in	State / province
1:1,000,000	10 km	15.78 mi	0.1 cm	0.063 in	Country (IMW)

Real distance = map distance × N (same units). Map distance = real distance ÷ N. Scale N = real distance ÷ map distance.

Worked Examples

Trail on a USGS topo: a trail measures 4.75 in with a string on a 1:24,000 map. 4.75 × 24,000 = 114,000 in = 9,500 ft = 1.80 mi (2.90 km). Add a few percent for switchbacks the string misses.
Find the scale: two towns 12 km apart are 4.8 cm apart on a road map. N = 1,200,000 cm ÷ 4.8 cm = 1:250,000.
Plot a distance: to mark 5 km on a 1:50,000 map, 500,000 cm ÷ 50,000 = 10 cm.
Coordinates: New York JFK (40.6413, −73.7781) to Los Angeles LAX (33.9416, −118.4085) is about 3,983 km (2,475 mi) along the great circle, starting on a bearing of about 274°.

Summary

A map scale defines how map distances relate to real-world distances — a 1:50,000 scale means 1 cm on the map equals 50,000 cm (500 m) in reality. This calculator takes a measured map distance and scale ratio, then converts the result to your chosen unit. It also works in reverse: enter a known real-world distance to find out how long it would appear on the map.

How it works

Select a scale preset (including USGS 1:24,000), type a ratio such as 1:50000, or enter a verbal scale like 1 inch = 1 mile.
Choose your input unit (cm, mm, or inches) and measure the distance on the map.
Enter the map distance value in the input field.
The calculator instantly shows the real-world distance in multiple units.
Use Real → Map to find the map length of a known distance, or Find Scale to work out a map's scale from one measured distance.
For two places with known coordinates, use the latitude/longitude card to get the great-circle distance and initial bearing.

Use cases

Measure hiking trail lengths on topographic maps before setting out.
Estimate driving distances from a road atlas when GPS is unavailable.
Plan cycling or walking routes on city or regional maps.
Calculate land areas or property boundaries from survey maps.
Compare distances across different map scales for travel planning.
Convert scaled architectural or engineering drawings to real dimensions.
Determine cross-country distances from small-scale atlas maps.
Verify GPS readings against paper map measurements.

Frequently Asked Questions

Last updated: 2026-10-09 · Reviewed by Nham Vu