25 mm = 0.984252 in (millimeter → inch)
25 mm = 0.984252 in
25 millimeters (mm) equals 0.984252 inches (in). The conversion uses the exact factor 0.0393701: 25 × 0.0393701 = 0.984252.
Inches = Millimeters × 0.0393701How 25 millimeters compares to its arithmetic neighbours, converted to inches.
| Relation | millimeters | inches |
|---|---|---|
| ÷10 | 2.5 mm | 0.0984252 in |
| ÷2 (half) | 12.5 mm | 0.492126 in |
| ×1 (this value) | 25 mm | 0.984252 in |
| ×2 (double) | 50 mm | 1.9685 in |
| ×5 | 125 mm | 4.92126 in |
| ×10 | 250 mm | 9.84252 in |
Millimetres to inches divides by 25.4 (since 1 in = 25.4 mm exactly). A 10 mm wrench is 0.394 in; a 5.5 mm hex key is 0.217 in, almost exactly the standard 7/32 in size. Most engineering drawings and machine-shop specs live in millimetres or thousandths of an inch ("thou" / "mils"); converting between them is routine when sourcing fasteners or aftermarket parts across the Atlantic. Round only at the end of a multi-step calculation to avoid compounding errors.
Machinists sourcing replacement fasteners for imported machinery translate metric drawing callouts into inch-based stock on the shelf. An M6 bolt has a 6 mm shank, which is 0.236 in — close to but not the same as a 1/4 in (0.25 in) imperial bolt, and forcing the wrong one strips threads. A 0.5 mm pitch difference is only 0.02 in, easy to miss by eye, so always convert the exact millimetre spec rather than eyeballing the nearest inch fraction.
Start with your value in millimeters.
Multiply the millimeter value by 0.0393701. This is the exact conversion factor from millimeters to inches.
The product is your value in inches. For example, 5 mm × 0.0393701 = 0.19685 in.
The exact factor from millimeters to inches is 0.0393701.
Inches = Millimeters × 0.0393701
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Millimeters (mm) | Inches (in) |
|---|---|
| 0.1 mm | 0.003937 in |
| 0.25 mm | 0.0098425 in |
| 0.5 mm | 0.019685 in |
| 1 mm | 0.03937 in |
| 2 mm | 0.07874 in |
| 3 mm | 0.11811 in |
| 4 mm | 0.15748 in |
| 5 mm | 0.19685 in |
| 6 mm | 0.23622 in |
| 7 mm | 0.27559 in |
| 8 mm | 0.31496 in |
| 9 mm | 0.35433 in |
| 10 mm | 0.3937 in |
| 11 mm | 0.43307 in |
| 12 mm | 0.47244 in |
| 13 mm | 0.51181 in |
| 14 mm | 0.55118 in |
| 15 mm | 0.59055 in |
| 16 mm | 0.62992 in |
| 18 mm | 0.70866 in |
| 20 mm | 0.7874 in |
| 22 mm | 0.86614 in |
| 24 mm | 0.94488 in |
| 25 mm | 0.98425 in |
| 28 mm | 1.1024 in |
| 30 mm | 1.1811 in |
| 32 mm | 1.2598 in |
| 36 mm | 1.4173 in |
| 40 mm | 1.5748 in |
| 45 mm | 1.7717 in |
| 48 mm | 1.8898 in |
| 50 mm | 1.9685 in |
| 60 mm | 2.3622 in |
| 70 mm | 2.7559 in |
| 75 mm | 2.9528 in |
| 80 mm | 3.1496 in |
| 90 mm | 3.5433 in |
| 100 mm | 3.937 in |
| 125 mm | 4.9213 in |
| 150 mm | 5.9055 in |
| 200 mm | 7.874 in |
| 250 mm | 9.8425 in |
| 300 mm | 11.811 in |
| 400 mm | 15.748 in |
| 500 mm | 19.685 in |
| 600 mm | 23.622 in |
| 750 mm | 29.528 in |
| 800 mm | 31.496 in |
| 900 mm | 35.433 in |
| 1000 mm | 39.37 in |
A credit card is about 0.76 mm thick. Standard A4 paper is 0.1 mm thick. A pencil lead is around 2 mm in diameter. In inches, that gives you: 1 mm = 0.0393701 in, 10 mm = 0.393701 in, 100 mm = 3.93701 in.
The millimeter (mm) is a metric unit of length equal to one-thousandth of a meter. It is the working unit of engineering drawings, precision manufacturing, electronics, and most consumer-goods specifications outside the United States. A credit card is about 0.76 mm thick; the diameter of a pencil lead is around 2 mm.
The inch (in) is a unit of length in the imperial and US customary systems, defined as exactly 25.4 millimeters since the 1959 international yard and pound agreement. It is the standard unit in the US for screen sizes, lumber, fasteners, and personal height when given in feet-and-inches form. Twelve inches make one foot.
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