Micrometers to Mils Converter
Enter the length in micrometers below to convert it to mils.
Convert Micrometers to Mils
Enter a value in micrometers (µm) to convert to mils (mil).
Micrometers to Mils 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 (mil) | Fraction — Nearest 1/64 (Reduced) | Nearest 1/16 (Tape) |
|---|---|---|---|
1 µm★ Common | 0.03937 mil | 3/64 mil | 1/16 mil |
2 µm★ Common | 0.07874 mil | 5/64 mil | 1/16 mil |
3 µm★ Common | 0.11811 mil | 1/8 mil | 1/8 mil |
4 µm | 0.15748 mil | 5/32 mil | 3/16 mil |
5 µm★ Common | 0.19685 mil | 13/64 mil | 3/16 mil |
6 µm★ Common | 0.23622 mil | 15/64 mil | 1/4 mil |
7 µm | 0.275591 mil | 9/32 mil | 1/4 mil |
8 µm★ Common | 0.314961 mil | 5/16 mil | 5/16 mil |
9 µm | 0.354331 mil | 23/64 mil | 3/8 mil |
10 µm★ Common | 0.393701 mil | 25/64 mil | 3/8 mil |
11 µm | 0.433071 mil | 7/16 mil | 7/16 mil |
12 µm★ Common | 0.472441 mil | 15/32 mil | 1/2 mil |
How to Convert Micrometers to Mils
To convert micrometers to mils, multiply the length by the following conversion ratio: 0.0393701 mils/micrometer.
Since one micrometer is equal to 0.0393701 mils, you can use this simple formula to convert:
The length in mils is equal to the length in micrometers multiplied by 0.0393701.
For example, here's how to convert 5 micrometers to mils using the formula above.
How Many Mils Are in a Micrometer?
There are 0.0393701 mils in a micrometer, which is why we use this value in the formula above.
Our micrometer fraction and decimal calculator can convert micrometers and mils, and it automatically converts the results to US customary, imperial, and SI metric values.
Micrometers and mils 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 0.000197 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 5 micrometers (µm) into fractional inches:
- Find the decimal inches result: Convert 5 µm to inches to get 0.000197 in.
- Separate the whole inches from the decimal part: Keep the whole number 0 aside, leaving the decimal remainder 0.000197.
- Multiply the decimal part by your desired fraction denominator (16, 32, or 64) and round half up: Multiply 0.000197 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 Mil?
A mil is a unit of length equal to 0.0000254 meters (m), the base unit for length. One thousandth of an inch (0.001 in = 0.0254 mm), used in manufacturing tolerances and film thickness. [2]
The mil is classified as a US customary and imperial unit of length. Mils can be abbreviated as mil; for example, 1 mil can be written as 1 mil.
When working with mils (mil) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, mils (mil) are widely used across fine-tolerance laboratory, analytical, and micro-scale length measurements within US customary and imperial workflows, engineering documentation, and technical data sheets.
When converting length between micrometers (µm) and mils (mil), keep full floating-point precision (1 µm = 0.0393701 mil; 1 mil = 25.4 µm) during intermediate calculations and round only the final mil figure to match your instrument tolerance.
More Micrometer & Mil Conversions
Need to calculate in the opposite direction? Use our mils to micrometers calculator to switch your starting unit immediately. You can also explore related tools such as converting mils to micrometers, converting millimeters to mils, or converting micrometers to millimeters.
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Length)·Length Metrology Standard — Micrometers (µm) to Mils (mil)
- [2]BIPM SpecificationBIPM (SI Base Unit: Metre (m))·Unit Specifications: Micrometer (Micron) (µm) & Mil (Thou) (mil)
- [3]NIST HB 133 ReferenceNIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (µm to mil)