Length

mm to km conversion

Convert millimetre (mm) to kilometre (km). Length units span pipe diameters (mm, inch), plant dimensions (m, ft), and roughness (µm) — mixing metric and imperial is routine.

1 mm = 1e-6 km

Formula

To convert millimetre to kilometre, multiply the mm value by 1e-6. To go the other way, divide by 1e-6 (or multiply by 1000000).

mm to km conversion table

mmkm
11e-6
22e-6
55e-6
101e-5
252.5e-5
505e-5
1000.0001
2500.00025
5000.0005
10000.001

Used in practice

Pipe sizes are labelled in inches (NPS) but calculated in mm; equipment layouts mix metres and feet.

Velocity scales with the inverse square of diameter, so a small length error compounds quickly in flow calculations.

Worked example. A length of 100 mm is 0.0001 km.

Frequently asked questions

How do you convert millimetre to kilometre?

Multiply the value in mm by 1e-6 to get km. For example, 10 mm = 1e-5 km.

What is 1 mm in km?

1 mm equals 1e-6 km.

Where is this conversion used?

Pipe sizes are labelled in inches (NPS) but calculated in mm; equipment layouts mix metres and feet.

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