Length converter

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.

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, some trades and almost every American website. Converting before you compare is how a 5 km parkrun does not become a “5 mile” run in someone’s head.

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 or the 1.6 km-per-mile shortcut. Five kilometres is 3.10686 miles, not “about 3” and not 5.

Building work is usually dimensioned in millimetres even when the conversation is in metres. A 2.4 m ceiling is 2,400 mm on the drawing. Convert once, then stay in that unit for the rest of the job.

Questions