Millimetres to Inches Converter
Convert millimetres to inches instantly. The result shows both the precise decimal inches and the nearest useful fractional inch. 1 mm = 0.0393700787 inches.
One inch is exactly 25.4 millimetres, so one millimetre equals 0.0393700787 inches. To convert millimetres to inches, divide by 25.4 (or multiply by 0.0393700787).
How to convert millimetres to inches
Millimetres to inches conversion table
Frequently asked questions
How do I convert millimetres to inches?
Divide the number of millimetres by 25.4 (or multiply by 0.0393700787). For example, 50 mm ÷ 25.4 = 1.97 inches. The calculator above also shows the nearest useful fractional inch.
How many millimetres are in an inch?
There are exactly 25.4 millimetres in one inch, so 1 millimetre equals 0.0393700787 inches. This is the internationally agreed definition used since 1959.
What is 3.5 mm in inches?
3.5 mm equals 0.1378 inches (3.5 ÷ 25.4 = 0.13780), which is about 9/64 of an inch. See our dedicated 3.5 mm in inches page for the full breakdown.
Why does the calculator show a fractional inch?
For practical workshop and engineering use, decimal inches are often rounded to the nearest common fraction (down to 1/64). The calculator shows both the precise decimal and the nearest fractional inch.
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