Length Converter

The length converter instantly converts between all common length and distance units — metric (km, m, cm, mm) and imperial (miles, yards, feet, inches) — as well as nautical miles used in aviation and shipping. Type a value, choose your units, and the result appears immediately. A reference scale shows the relative size of common lengths to help you build intuition for unfamiliar units.

Visual Scale Comparison

Relative length reference1 inch = 2.54 cm1 foot = 30.48 cm1 yard = 91.44 cm1 metre = 100 cm1 km = 100000 cm (truncated)

How to Use

  1. Type the number you want to convert in the Value field at the top.
  2. Select the unit you are converting FROM in the left dropdown — for example kilometres.
  3. Select the unit you want to convert TO in the right dropdown — for example miles.
  4. The result appears instantly below without needing to click any button.
  5. Click the ↔ Swap button to reverse the direction and convert back immediately.

Formula

All length conversions work by first converting to the base unit (metre), then dividing by the target unit's factor.

Result = (Input × from_factor) / to_factor

For example: 5 miles to km
5 × 1609.344 / 1000 = 8.047 km

Key exact conversion facts: 1 inch = 2.54 cm, 1 foot = 12 inches = 30.48 cm, 1 yard = 3 feet = 91.44 cm, 1 mile = 1760 yards = 1609.344 m, and 1 nautical mile = 1852 m. Metric units use powers of 10, so conversion is a simple multiply or divide by 10, 100, 1000, and so on.

Worked Example

Convert 26.2 miles, a marathon distance, to kilometres.

26.2 miles × 1609.344 m/mile = 42164.8 m
42164.8 m ÷ 1000 = 42.165 km

A modern marathon is officially 42.195 km, so this rounded mile value is very close.

Convert 5 feet 11 inches to centimetres: 5 feet = 5 × 30.48 = 152.4 cm, and 11 inches = 11 × 2.54 = 27.94 cm. Total height = 180.34 cm.

Common Length Conversions

FromToMultiply by
1 inchcm2.54
1 footcm30.48
1 yardmetres0.9144
1 milekm1.60934
1 kmmiles0.621371
1 metrefeet3.28084
1 cminches0.393701
1 nautical milekm1.852
1 metreyards1.09361
5 feetcm152.4

FAQ

How many centimetres are in an inch?

There are exactly 2.54 centimetres in one inch. This is a defined relationship, not a rounded estimate.

What is the difference between a mile and a nautical mile?

A land mile is 1609.344 metres. A nautical mile is 1852 metres and is based on latitude, so it is used in aviation and shipping.

How do you convert height from feet and inches to centimetres?

Convert feet to centimetres by multiplying by 30.48, convert inches by multiplying by 2.54, then add the two results.

What is the metric system and why does it use powers of 10?

The metric system is a decimal measurement system. Prefixes such as kilo, centi and milli represent powers of 10, which makes conversion easy.

How many metres are in a kilometre?

There are 1000 metres in one kilometre.