Length Converter — Inches, Feet, Meters, Miles, km

1 inch = 2.54 cm (exact, by definition)
1 foot = 12 inches = 30.48 cm
1 yard = 3 feet = 0.9144 m
1 mile = 5,280 feet = 1,609.344 m
1 km = 1,000 m = 0.62137 miles

The inch-to-centimeter conversion (1 in = 2.54 cm) is an exact defined value, not an approximation. All imperial-to-metric conversions derive from this single definition.

Inches to cm

=A1*2.54

cm to inches

=A1/2.54

Miles to km

=A1*1.609344

km to miles

=A1/1.609344

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Imperial vs Metric Length Units

The metric system organizes length in powers of 10: 10 millimeters = 1 centimeter, 100 centimeters = 1 meter, 1,000 meters = 1 kilometer. This decimal structure makes metric conversions trivially simple — multiply or divide by 10, 100, or 1,000.

Imperial units have no systematic numerical relationship. 12 inches per foot, 3 feet per yard, 1,760 yards per mile (5,280 feet) — these numbers arose from historical convenience and have been standardized over centuries. They are deeply embedded in US infrastructure, construction, and everyday conversation, which is why the US has resisted metrication despite the mathematical inconvenience.

The single anchor between the two systems is the defined relationship: 1 inch = 2.54 centimeters exactly, established by international agreement in 1959. All other imperial-to-metric conversions — feet, yards, miles — derive mathematically from this one definition.

Quick Mental Conversion Benchmarks

For distance: 1 kilometer ≈ 0.6 miles (more precisely 0.621). So 100 km/h ≈ 62 mph. A 5K race is 3.1 miles. A marathon (42.195 km) is 26.2 miles. For everyday objects: 1 inch is the width of a US quarter. 1 foot is roughly the length of a standard ruler. 1 meter is roughly the height of a kitchen counter. 1 km is roughly the length of 9 football fields.

Frequently Asked Questions

Exactly 2.54 cm = 1 inch. This is a defined value, not an approximation, established by international agreement in 1959. Therefore: 1 foot = 30.48 cm, 1 yard = 91.44 cm, 1 mile = 160,934.4 cm — all exact derived values.

Multiply miles by 1.6 for a quick approximation (actual: 1.60934). Example: 60 miles × 1.6 = 96 km (actual: 96.56 km). For km to miles, multiply by 0.6. Example: 100 km × 0.6 = 60 miles (actual: 62.1 miles). Close enough for navigation estimates.

1 nautical mile = 1,852 meters = approximately 1.151 statute miles. Nautical miles are used in maritime and aviation navigation because 1 nautical mile equals 1 minute of arc of latitude — a direct relationship to geographic coordinates that simplifies chart navigation.

Path dependency and the high cost of systemic change. The US has attempted metrication multiple times — the Metric Conversion Act of 1975 encouraged voluntary adoption, and the 1988 Omnibus Trade Act required federal agencies to use metric. Industry and science largely use metric; everyday consumer contexts have resisted. Every road sign, construction blueprint, and appliance spec in the US would need updating in a full transition.