Micrometers to meters, convert µm to m.

To convert micrometers to meters, divide the micrometers by 1,000,000. So 1 µm is 0.000001 m, 100 µm is 0.0001 m and 2.5 µm is 0.0000025 m. "Micro" means one millionth, so the factor is exact. You can also write it as multiplying by 10^-6. The micrometer is the same unit as the old "micron".

How to use the converter

1. Type the size in the Micrometers (µm) box. The page opens on 2.5 µm. You do not need the µ sign for the unit, since the box takes only the number.
2. Read meters in the big result. The cards show millimeters, centimeters and nanometers.
3. Small results have many decimals, so leave Decimals on Auto, which shows enough digits.
4. Use Copy result, Copy link or Print chart, and click a row of Common values to load it.
5. The swap button (or S) turns meters into micrometers.

What the numbers are

The NIST list of SI prefixes (checked 26 Oct 2026) gives micro (symbol µ) as 10^-6, a millionth, and milli as 10^-3. NIST Special Publication 811, Appendix B.8 lists the micron as exactly 1 × 10^-6 m, equal to 1 micrometer. So 1 µm = 0.001 mm = 1,000 nm = 0.000001 m. The ladder:

Particle sizes

The US EPA page on particulate matter (checked 26 Oct 2026) says PM10 particles are generally 10 micrometers and smaller, and PM2.5 particles are generally 2.5 micrometers and smaller. It also notes that the average human hair is about 70 micrometers across. In meters:

Worked examples

• 50 µm. 50 ÷ 1,000,000 = 0.00005 m, or 0.05 mm.
• 0.8 µm, a surface finish. 0.0000008 m.
• 25 µm, a thin film. 0.000025 m.
• 1,000 µm. 0.001 m, exactly 1 mm.
• 250,000 µm. 0.25 m, which is 25 cm.

Filters and coatings

Pore sizes and film thicknesses are quoted in micrometers. A filter with 5 µm pores has openings of 0.000005 m. A coating 40 µm thick is 0.04 mm, or 0.00004 m. Reading a spec in meters and a gauge in micrometers is where this page helps.

Scientific notation

Very small meters are easier to read as powers of ten. 2.5 µm is 2.5 × 10^-6 m. 70 µm is 7 × 10^-5 m. To get the power, count the decimal places when you divide by a million: 6 places move the point six steps to the left. The scientific calculator takes numbers in that form.

Mistakes to avoid

The most common is mixing µm with mm. A millimeter is 1,000 times a micrometer, so 70 µm is 0.07 mm and not 70 mm. Do not confuse µm with mm in a lab report or a filter rating. Another slip is losing a zero in the long decimal, so check the answer against the power of ten: 2.5 µm is 2.5 × 10^-6 m.

For millimeters see mm to m, and for the other end of the scale m to km.