Conversion tool
Length Converter
Convert between metric and imperial length units. All factors are exact values established by international agreement — not approximations.
Formula & conversion factors
1 inch = 0.0254 m (exact, by international yard and pound agreement, 1959)
1 foot = 0.3048 m (exact, 12 inches)
1 yard = 0.9144 m (exact, 3 feet)
1 mile = 1,609.344 m (exact, 5,280 feet)
1 nautical mile = 1,852 m (exact, by international agreement)
General form: value_m = value_unit × factor_to_m
result = value_m ÷ factor_of_target_unit
1 foot = 0.3048 m (exact, 12 inches)
1 yard = 0.9144 m (exact, 3 feet)
1 mile = 1,609.344 m (exact, 5,280 feet)
1 nautical mile = 1,852 m (exact, by international agreement)
General form: value_m = value_unit × factor_to_m
result = value_m ÷ factor_of_target_unit
1Worked example: 170 cm in feet and inches. 170 × 0.01 = 1.70 m → ÷ 0.3048 = 5.577 ft → 5 ft + 0.577 × 12 = 5 ft 6.93 in (a common height-conversion query).
Reference standard: Base unit: metre (m), the SI base unit of length.
Imperial–metric factors established by the International Yard and Pound Agreement (1959),
adopted by the US, UK, Canada, Australia, New Zealand, and South Africa.
Common questions
How many cm are in an inch?
Exactly 2.54 cm. This is not an approximation — 1 inch was defined as exactly 25.4 mm by international agreement in 1959.
How do you convert cm to inches?
Divide the cm value by 2.54. For example, 10 cm ÷ 2.54 = 3.937 inches.
What is the difference between a nautical mile and a statute mile?
A nautical mile (1,852 m) is about 15% longer than a statute mile (1,609.344 m). Nautical miles are used in aviation and maritime navigation because one nautical mile equals one minute of latitude.