Length

µm to mm conversion

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

1 µm = 0.001 mm

Formula

To convert micrometre to millimetre, multiply the µm value by 0.001. To go the other way, divide by 0.001 (or multiply by 1000).

µm to mm conversion table

µm	mm
1	0.001
2	0.002
5	0.005
10	0.01
25	0.025
50	0.05
100	0.1
250	0.25
500	0.5
1000	1

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 100000 µm is 100 mm.

Frequently asked questions

How do you convert micrometre to millimetre?

Multiply the value in µm by 0.001 to get mm. For example, 10 µm = 0.01 mm.

What is 1 µm in mm?

1 µm equals 0.001 mm.

Where is this conversion used?