Length
converter
Metric on one side, imperial on the other — pick your units, type a value, done. Millimeters to miles and everything between, using the exact defined factors.
One base unit, exact bridges
Every conversion routes through the meter. Metric units are clean powers of ten; the imperial bridge has been exactly defined since 1959: one inch is precisely 2.54 cm, which fixes the foot (0.3048 m), yard (0.9144 m) and mile (1,609.344 m) with zero rounding.
1 mi = 1.609344 km · 1 km ≈ 0.6214 mi
Quick mental swaps
Kilometers to miles: multiply by 0.6 (or take five-eighths). Meters to feet: multiply by 3.3. Centimeters to inches: divide by 2.5. All within a couple percent — good enough for conversation, while the tool above stays exact. For area jobs like flooring, the square footage calculator works in the units builders quote.
Length FAQ
Exactly 2.54 — defined by international agreement in 1959, not measured. Every imperial length conversion derives from it.
Divide by 1.609344, or mentally multiply by 0.6: a 10 km run is about 6.2 miles.
About 3.281 feet. Going the other way, a foot is exactly 0.3048 meters.
Because they're exact definitions, not measurements — 1 mile is precisely 1,609.344 m. The tool uses the full exact factor so no error accumulates.