Micrometers to Millimeters Converter
Enter the length in micrometers below to convert it to millimeters.
Convert Micrometers to Millimeters
Enter a value in micrometers (µm) to convert to millimeters (mm).
Micrometers to Millimeters Conversion Chart (1–40 Continuous)
Continuous 1 to 40 micrometers lookup table with exact decimals and reduced nearest 1/64 fractions. Highlighted rows mark common shop and ruler values.
| Micrometers (µm) | Decimal (mm) | Fraction — Nearest 1/64 (Reduced) | Nearest 1/16 (Tape) |
|---|---|---|---|
1 µm★ Common | 0.001 mm | 0 mm | 0 mm |
2 µm★ Common | 0.002 mm | 0 mm | 0 mm |
3 µm★ Common | 0.003 mm | 0 mm | 0 mm |
4 µm | 0.004 mm | 0 mm | 0 mm |
5 µm★ Common | 0.005 mm | 0 mm | 0 mm |
6 µm★ Common | 0.006 mm | 0 mm | 0 mm |
7 µm | 0.007 mm | 0 mm | 0 mm |
8 µm★ Common | 0.008 mm | 1/64 mm | 0 mm |
9 µm | 0.009 mm | 1/64 mm | 0 mm |
10 µm★ Common | 0.01 mm | 1/64 mm | 0 mm |
11 µm | 0.011 mm | 1/64 mm | 0 mm |
12 µm★ Common | 0.012 mm | 1/64 mm | 0 mm |
How to Convert Micrometers to Millimeters
To convert micrometers to millimeters, multiply the length by the following conversion ratio: 0.001 millimeters/micrometer.
Since one micrometer is equal to 0.001 millimeters, you can use this simple formula to convert:
The length in millimeters is equal to the length in micrometers multiplied by 0.001.
For example, here's how to convert 500 micrometers to millimeters using the formula above.
How Many Millimeters Are in a Micrometer?
There are 0.001 millimeters in a micrometer, which is why we use this value in the formula above.
Our micrometer fraction and decimal calculator can convert micrometers and millimeters, and it automatically converts the results to US customary, imperial, and SI metric values.
Micrometers and millimeters are both units used to measure length. Keep reading to learn more about each unit.
How to Convert Micrometers to Fractional Inches (1/16″, 1/32″ & 1/64″)
Plain-language method for turning decimal inches into a standard tape-measure or machinist ruler fraction
Calculators give you a decimal number (such as 0.019685 in), but tape measures and woodworking rulers are marked in binary fractions of an inch—most commonly 1/16″ on carpenter tapes, 1/32″ on fine woodworking rules, and 1/64″ on machinist scales.
Here is the step-by-step worked example for converting 500 micrometers (µm) into fractional inches:
- Find the decimal inches result: Convert 500 µm to inches to get 0.019685 in.
- Separate the whole inches from the decimal part: Keep the whole number 0 aside, leaving the decimal remainder 0.019685.
- Multiply the decimal part by your desired fraction denominator (16, 32, or 64) and round half up: Multiply 0.019685 by 16, 32, or 64, then round to the nearest whole number (values ending in .5 round up).
- Reduce the fraction to lowest terms: If the rounded top number (numerator) is even, divide both top and bottom by 2 (or their Greatest Common Divisor) until the top number is odd, then combine with your whole inches.
What Is a Micrometer?
A micrometer is a unit of length equal to 1/1,000,000 of a meter (0.000001 m). One millionth of a meter (10⁻⁶ m), also known as a micron. [1]
The micrometer is classified as a metric and SI-compatible unit of length. Micrometers can be abbreviated as µm; for example, 1 micrometer can be written as 1 µm.
In the metric system, "micro" is the standard SI prefix for millionths, or 10⁻⁶. This makes the micrometer (µm) a convenient decimal multiple of the meter (m).
In practice, micrometers (µm) are widely used across fine-tolerance laboratory, analytical, and micro-scale length measurements within SI metric workflows, engineering documentation, and technical data sheets.
What Is a Millimeter?
A millimeter is a metric unit of length equal to one-thousandth (1/1,000) of a meter or one-tenth (1/10) of a centimeter. By international definition, there are exactly 25.4 millimeters in one inch. [2]
The millimeter, or millimetre, is a standard SI metric unit of length. Millimeters can be abbreviated as mm; for example, 1 millimeter can be written as 1 mm.
In the metric system, "milli" is the prefix for thousandths, or 10⁻³. Millimeters are the default unit on mechanical engineering drawings and architectural blueprints worldwide.
Millimeters are commonly measured using metric steel rules, digital vernier calipers, depth gauges, and micrometers in CNC machining, 3D printing, automotive fasteners, and precision manufacturing.
When converting length between micrometers (µm) and millimeters (mm), keep full floating-point precision (1 µm = 0.001 mm; 1 mm = 1,000 µm) during intermediate calculations and round only the final millimeter figure to match your instrument tolerance.
More Micrometer & Millimeter Conversions
Need to calculate in the opposite direction? Use our millimeters to micrometers calculator to switch your starting unit immediately. You can also explore related tools such as converting millimeters to micrometers, converting inches to millimeters, or converting meters to millimeters.
Convert from Micrometers
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Length)·Length Metrology Standard — Micrometers (µm) to Millimeters (mm)
- [2]BIPM SpecificationBIPM (SI Base Unit: Metre (m))·Unit Specifications: Micrometer (Micron) (µm) & Millimeter (mm)
- [3]NIST HB 133 ReferenceNIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (µm to mm)