OzCalc
EverydayLast reviewed 2026-08-19

Length converter

Convert millimetres, centimetres, metres, kilometres, inches, feet, yards and miles.

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What the result means

Length conversion is a change of unit, not a change of distance. Five kilometres is the same stretch of road whether you call it 5 km or about 3.1 miles.

How it is calculated

to = from × (factorFrom ÷ factorTo), using metres as the common base
  • Value: The amount in the starting unit.
  • From / To: Units from the same measurement family.

Each unit is expressed as a multiple of a metre. The converter multiplies into metres, then divides into the target unit.

Assumptions

  • Exact international conversion factors, then rounded for display.
  • No surveying, temperature expansion or commodity density adjustments.

Worked example

5 km in miles

A parkrun is advertised as 5 km. A visitor thinks in miles.

Base
5 km = 5,000 m
Miles
5,000 ÷ 1,609.344 ≈ 3.107 miles

Five kilometres is a little over three miles, not five miles and not a 5 km “rounded down” 3-mile course.

Metric is the legal Australian unit

Road distances, building plans and most product labels in Australia use millimetres, metres and kilometres. Inches and feet still appear on imported goods, screens and some trades.

An inch is defined as exactly 25.4 millimetres. That makes every imperial conversion here exact before rounding, rather than a surveyor’s chain approximation.

Questions

Is a nautical mile included?

No. Nautical miles are a navigation unit (1,852 m) and belong in a marine tool, not a general length converter.

Why not use 1.6 km per mile?

1.6 is a mental shortcut. The defined mile is 1,609.344 metres, which this converter uses.

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Sources

Everyday · Last reviewed 2026-08-19

Estimates only. Not tax, legal or financial advice. Check official sources before relying on a figure.