How many millimeters are in 1 micrometer?

1 µm equals 0.001 mm. This is an exact conversion factor defined by NIST.

How do I convert micrometers to millimeters?

Multiply the value in µm by the conversion factor. For example, 10 µm = 0.01 mm. Use our calculator above for instant results.

Is the micrometers to millimeters conversion exact?

Yes, this conversion is mathematically exact based on the international definition of these units (NIST SP 811).

Can I convert micrometers to millimeters offline?

Yes! OmniConvert runs entirely in your browser — no internet connection needed after the page loads. Your data never leaves your device, ensuring complete privacy.

What is the difference between micrometers and millimeters?

Micrometers (µm) and Millimeters (mm) are both units of length but belong to different measurement systems. 1 µm = 0.001 mm. Use the converter above to switch between them instantly.

Micrometers to Millimeters (µm → mm) — Free Online Converter

µm → mm Reference Table

µm	mm
0.001 µm	0.000001 mm
0.002 µm	0.000002 mm
0.003 µm	0.000003 mm
0.004 µm	0.000004 mm
0.005 µm	0.000005 mm
0.006 µm	0.000006 mm
0.007 µm	0.000007 mm
0.008 µm	0.000008 mm
0.009 µm	0.000009 mm
0.01 µm	0.00001 mm
0.02 µm	0.00002 mm
0.03 µm	0.00003 mm
0.04 µm	0.00004 mm
0.05 µm	0.00005 mm
0.06 µm	0.00006 mm
0.07 µm	0.00007 mm
0.08 µm	0.00008 mm
0.09 µm	0.00009 mm
0.1 µm	0.0001 mm
0.2 µm	0.0002 mm
0.3 µm	0.0003 mm
0.4 µm	0.0004 mm
0.5 µm	0.0005 mm
0.6 µm	0.0006 mm
0.7 µm	0.0007 mm
0.8 µm	0.0008 mm
0.9 µm	0.0009 mm
1 µm	0.001 mm
1.5 µm	0.0015 mm
2 µm	0.002 mm
2.5 µm	0.0025 mm
3 µm	0.003 mm
3.5 µm	0.0035 mm
4 µm	0.004 mm
4.5 µm	0.0045 mm
5 µm	0.005 mm
5.5 µm	0.0055 mm
6 µm	0.006 mm
6.5 µm	0.0065 mm
7 µm	0.007 mm
7.5 µm	0.0075 mm
8 µm	0.008 mm
8.5 µm	0.0085 mm
9 µm	0.009 mm
9.5 µm	0.0095 mm
10 µm	0.01 mm
11 µm	0.011 mm
12 µm	0.012 mm
13 µm	0.013 mm
14 µm	0.014 mm
15 µm	0.015 mm
16 µm	0.016 mm
17 µm	0.017 mm
18 µm	0.018 mm
19 µm	0.019 mm
20 µm	0.02 mm
25 µm	0.025 mm
30 µm	0.03 mm
35 µm	0.035 mm
40 µm	0.04 mm
45 µm	0.045 mm
50 µm	0.05 mm
55 µm	0.055 mm
60 µm	0.06 mm
65 µm	0.065 mm
70 µm	0.07 mm
75 µm	0.075 mm
80 µm	0.08 mm
85 µm	0.085 mm
90 µm	0.09 mm
95 µm	0.095 mm
100 µm	0.1 mm
120 µm	0.12 mm
125 µm	0.125 mm
130 µm	0.13 mm
140 µm	0.14 mm
150 µm	0.15 mm
160 µm	0.16 mm
175 µm	0.175 mm
180 µm	0.18 mm
200 µm	0.2 mm
225 µm	0.225 mm
250 µm	0.25 mm
275 µm	0.275 mm
300 µm	0.3 mm
350 µm	0.35 mm
400 µm	0.4 mm
450 µm	0.45 mm
500 µm	0.5 mm
600 µm	0.6 mm
700 µm	0.7 mm
750 µm	0.75 mm
800 µm	0.8 mm
900 µm	0.9 mm
1000 µm	1 mm
1200 µm	1.2 mm
1250 µm	1.25 mm
1500 µm	1.5 mm
1750 µm	1.75 mm
2000 µm	2 mm
2500 µm	2.5 mm
3000 µm	3 mm
4000 µm	4 mm
4500 µm	4.5 mm
5000 µm	5 mm
6000 µm	6 mm
7000 µm	7 mm
7500 µm	7.5 mm
8000 µm	8 mm
9000 µm	9 mm
10000 µm	10 mm
15000 µm	15 mm
20000 µm	20 mm
25000 µm	25 mm
50000 µm	50 mm
75000 µm	75 mm
100000 µm	100 mm

Values based on NIST SP 811 conversion factors

Why Convert Micrometers to Millimeters?

Converting between micrometers (µm) and millimeters (mm) is one of the most common length conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert µm to mm saves time and prevents errors.

Length conversions between µm and mm are fundamental in construction, manufacturing, and international trade. Architects rely on precise conversions when adapting building plans between metric and imperial standards — a 1% error on a 30-meter wall translates to 30 cm of misalignment. Travelers frequently convert between kilometers and miles for road trips, while online shoppers need length conversions to verify clothing sizes, furniture dimensions, and screen diagonals across international retailers. In athletics, track distances (100m, 1500m, marathon) must be precisely converted for record comparisons across different measurement traditions.

How to Convert Micrometers to Millimeters

To convert micrometers to millimeters, use the following formula:

mm = µm × 0.001

Example: 1 µm = 0.001 mm

For example, 5 µm = 0.005 mm, 10 µm = 0.01 mm, and 100 µm = 0.1 mm. For larger values, 1000 µm = 1 mm. Conversely, 1 mm = 1000 µm. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Mistakes to Avoid

Confusing similar units: confusing nautical miles with regular miles, or yards with meters.
Decimal errors: moving the decimal point the wrong way (e.g., 100 cm = 1 m, not 10 m).
Approximation: assuming an inch is exactly 2.5 cm (it's 2.54 cm).

Pro Tips

Use 'approx' for mental math: 1 km is roughly 0.6 miles (or 2/3 for quick estimates).
Visualize: A meter is about a guitar length; an inch is a thumb width.
Ruler check: Most rulers show cm and inches together—great for quick checks.

What is a Micrometer?

A unit of length in the metric system equal to one millionth of a meter (1×10⁻⁶ m). Also known as a micron.

Widely used in microscopy, biology for measuring cell sizes, and in manufacturing for specifying tolerances.

What is a Millimeter?

The millimeter (mm) is a metric unit of length equal to one-thousandth of a meter (0.001 m). It is a standard unit in the International System of Units (SI).

Millimeters are used for precision engineering, manufacturing dimensions, rainfall measurement, and paper sizes (ISO 216). It represents small scale accuracy.

Micrometers → Millimeters

Micrometers to Millimeters Formula