Millimeters to Inches Conversion Table — Metric Sizes & Fractions
Complete reference: 1-100 mm + common metric sizes with nearest fractions
Any length-distance value in mm can be converted to in using the conversion factor:
- 1 millimeter = 0.0393701 inch
- in = mm ÷ 25.4
mm → in Quick Converter
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What is Millimeter (mm)?
Metric unit equal to one thousandth (1/1000) of a meter.
What is Inch (in)?
Imperial/US customary unit standardized as exactly 25.4 millimeters since 1959.
How to Convert Millimeter to Inch
Example
Convert 11 mm to in:
11 × 0.0393701 = 0.433071 in
Millimeters to Inches Conversion Table — Metric Sizes & Fractions
Values from 1 to 100 mm.
Common Metric Sizes in Inches
Standard metric sizes in drill bits, fasteners, and hardware — with decimal inch equivalents and nearest fractional inch (to 1/64"). Based on exact definition: 1 inch = 25.4 mm.
| mm | Decimal (in) | Nearest Fraction |
|---|---|---|
| 1 mm | 0.0394 | 3/64" |
| 1.5 mm | 0.0591 | 1/16" |
| 2 mm | 0.0787 | 5/64" |
| 2.5 mm | 0.0984 | 3/32" |
| 3 mm | 0.1181 | 1/8" |
| 3.5 mm | 0.1378 | 9/64" |
| 4 mm | 0.1575 | 5/32" |
| 4.5 mm | 0.1772 | 11/64" |
| 5 mm | 0.1969 | 13/64" |
| 6 mm | 0.2362 | 15/64" |
| 7 mm | 0.2756 | 9/32" |
| 8 mm | 0.3150 | 5/16" |
| 9 mm | 0.3543 | 23/64" |
| 10 mm | 0.3937 | 25/64" |
| 12 mm | 0.4724 | 15/32" |
| 14 mm | 0.5512 | 35/64" |
| 15 mm | 0.5906 | 19/32" |
| 16 mm | 0.6299 | 5/8" |
| 18 mm | 0.7087 | 45/64" |
| 19 mm | 0.7480 | 3/4" |
| 20 mm | 0.7874 | 25/32" |
| 22 mm | 0.8661 | 55/64" |
| 24 mm | 0.9449 | 15/16" |
| 25 mm | 0.9843 | 63/64" |
| 25.4 mm | 1.0000 | 1" |
Nearest fractions rounded to the closest 1/64". For precision work, use the decimal inch value.
Frequently Asked Questions
How do I convert millimeters to inches?
To convert millimeters to inches, divide the millimeter value by 25.4. For example, 50 mm ÷ 25.4 = 1.9685 inches.
Why is 25.4 the exact conversion factor?
Since 1959, the international inch has been defined as exactly 25.4 millimeters. This exact definition means the mm to inch conversion is always precise.
When is mm to inches conversion most useful?
This conversion is essential for translating metric hardware specifications (bolts, screws, drill bits) to imperial equivalents, working with manufacturing tolerances, and comparing international product dimensions.
What common metric sizes equal standard fractional inches?
Common equivalents: 3.175 mm = 1/8 in, 6.35 mm = 1/4 in, 9.525 mm = 3/8 in, 12.7 mm = 1/2 in, 19.05 mm = 3/4 in, and 25.4 mm = 1 in.
How accurate is this millimeters to inches conversion table?
This table is perfectly accurate as it uses the exact definition of 1 inch = 25.4 mm. The conversion is mathematically exact with no rounding in the conversion factor.
