Length • NIST Exact

Millimeters Micrometers

mm → µm

1 mm = 1,000 µmNIST Exact

NIST Exact

Based on U.S. National Institute of Standards

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mm → µm Reference Table

mm µm
0.001 mm 1 µm
0.002 mm 2 µm
0.003 mm 3 µm
0.004 mm 4 µm
0.005 mm 5 µm
0.006 mm 6 µm
0.007 mm 7 µm
0.008 mm 8 µm
0.009 mm 9 µm
0.01 mm 10 µm
0.02 mm 20 µm
0.03 mm 30 µm
0.04 mm 40 µm
0.05 mm 50 µm
0.06 mm 60 µm
0.07 mm 70 µm
0.08 mm 80 µm
0.09 mm 90 µm
0.1 mm 100 µm
0.2 mm 200 µm
0.3 mm 300 µm
0.4 mm 400 µm
0.5 mm 500 µm
0.6 mm 600 µm
0.7 mm 700 µm
0.8 mm 800 µm
0.9 mm 900 µm
1 mm 1000 µm
1.5 mm 1500 µm
2 mm 2000 µm
2.5 mm 2500 µm
3 mm 3000 µm
3.5 mm 3500 µm
4 mm 4000 µm
4.5 mm 4500 µm
5 mm 5000 µm
5.5 mm 5500 µm
6 mm 6000 µm
6.5 mm 6500 µm
7 mm 7000 µm
7.5 mm 7500 µm
8 mm 8000 µm
8.5 mm 8500 µm
9 mm 9000 µm
9.5 mm 9500 µm
10 mm 10000 µm
11 mm 11000 µm
12 mm 12000 µm
13 mm 13000 µm
14 mm 14000 µm
15 mm 15000 µm
16 mm 16000 µm
17 mm 17000 µm
18 mm 18000 µm
19 mm 19000 µm
20 mm 20000 µm
25 mm 25000 µm
30 mm 30000 µm
35 mm 35000 µm
40 mm 40000 µm
45 mm 45000 µm
50 mm 50000 µm
55 mm 55000 µm
60 mm 60000 µm
65 mm 65000 µm
70 mm 70000 µm
75 mm 75000 µm
80 mm 80000 µm
85 mm 85000 µm
90 mm 90000 µm
95 mm 95000 µm
100 mm 100000 µm
120 mm 120000 µm
125 mm 125000 µm
130 mm 130000 µm
140 mm 140000 µm
150 mm 150000 µm
160 mm 160000 µm
175 mm 175000 µm
180 mm 180000 µm
200 mm 200000 µm
225 mm 225000 µm
250 mm 250000 µm
275 mm 275000 µm
300 mm 300000 µm
350 mm 350000 µm
400 mm 400000 µm
450 mm 450000 µm
500 mm 500000 µm
600 mm 600000 µm
700 mm 700000 µm
750 mm 750000 µm
800 mm 800000 µm
900 mm 900000 µm
1000 mm 1000000 µm
1200 mm 1200000 µm
1250 mm 1250000 µm
1500 mm 1500000 µm
1750 mm 1750000 µm
2000 mm 2000000 µm
2500 mm 2500000 µm
3000 mm 3000000 µm
4000 mm 4000000 µm
4500 mm 4500000 µm
5000 mm 5000000 µm
6000 mm 6000000 µm
7000 mm 7000000 µm
7500 mm 7500000 µm
8000 mm 8000000 µm
9000 mm 9000000 µm
10000 mm 10000000 µm
15000 mm 15000000 µm
20000 mm 20000000 µm
25000 mm 25000000 µm
50000 mm 50000000 µm
75000 mm 75000000 µm
100000 mm 100000000 µm

Values based on NIST SP 811 conversion factors

Why Convert Millimeters to Micrometers?

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

Length conversions between mm and µm 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 Millimeters to Micrometers

To convert millimeters to micrometers, use the following formula:

µm = mm × 1000

Example: 1 mm = 1000 µm

For example, 5 mm = 5000 µm, 10 mm = 10000 µm, and 100 mm = 100000 µm. For larger values, 1000 mm = 1000000 µm. Conversely, 1 µm = 0.001 mm. 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 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.

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.

Frequently Asked Questions

How many micrometers are in 1 millimeter?

1 mm equals 1000 µm. This is an exact conversion factor defined by NIST.

How do I convert millimeters to micrometers?

Multiply the value in mm by the conversion factor. For example, 10 mm = 10000 µm. Use our calculator above for instant results.

Is the millimeters to micrometers conversion exact?

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

Can I convert millimeters to micrometers 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 millimeters and micrometers?

Millimeters (mm) and Micrometers (µm) are both units of length but belong to different measurement systems. 1 mm = 1000 µm. Use the converter above to switch between them instantly.

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