Microns to MM Converter

Convert micrometers (µm) to millimeters (mm) instantly. Type a value — the result updates as you type, and the swap button converts the other way.

Microns to mm formula

mm = µm ÷ 1000

1 micrometer = 0.001 millimeters · 1 millimeter = 1000 micrometers

To convert micrometers to millimeters, divide the value by 1000. For example, 100 µm:

mm = 100 ÷ 1000
mm = 0.1

So 100 µm = 0.1 mm.

Mental math shortcut

This conversion is exact, so there is no need to estimate: just divide by 1,000.

Microns to mm conversion table

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

mm back to Microns

The same values converted the other way, rounded for everyday use:

Millimeters	Micrometers
0.001 mm	1 µm
0.005 mm	5 µm
0.01 mm	10 µm
0.025 mm	25 µm
0.05 mm	50 µm
0.1 mm	100 µm
0.25 mm	250 µm
0.5 mm	500 µm

About the units

Micrometers (µm)

A micrometer (micron, µm) is one millionth of a meter or one thousandth of a millimeter. Filters, fibers, bacteria and coating thicknesses are measured in microns.

Millimeters (mm)

A millimeter is one thousandth of a meter (0.1 cm). It is used for small, precise measurements like rainfall, screws and paper thickness.

Frequently asked questions

How many millimeters are in a micrometer?

One micrometer equals 0.001 millimeters.

What is 100 Microns in mm?

100 µm = 0.1 mm.

How do I convert mm back to Microns?

Multiply the millimeters by 1000.