um to mm Converter - Micrometer to Millimeter

Micrometer (μm) (um) to Millimeter (mm)

Direct answer

1 um = 0.001 mm

mm = um × 0.001

Converter

Input

Result

0.001mm

mm = um × 0.001

um = mm × 1,000

Example: 10 um = 10 × 0.001 = 0.01 mm.

Express both um and mm in the same base unit m (meter), then cancel the shared base unit.

1
Rewrite um in the base unit
$1 um = 0.000001 m$
2
Rewrite mm in the base unit
$1 mm = 0.001 m$
3
Forward conversion
$1 um = \frac{0.000001 m}{0.001 m} \times 1 mm = \frac{0.000001}{0.001} mm = 0.001 mm$
4
Reverse conversion
$1 mm = \frac{0.001 m}{0.000001 m} \times 1 um = \frac{0.001}{0.000001} um = 1, 000 um$

A guarded explanation for this pair page covering definition, principle, assumptions, and cautions.

Guarded output

AI text is for interpretation only. The page calculator remains the source of truth for numeric results.

1 um = 0.001 mm.

10 um = 0.01 mm.

100 um = 0.1 mm.

Use mm = um × 0.001.

1 mm = 1,000 um.

Use the conversion factor and round the result to the precision required by your calculation.