Millimeters to Inches Converter
Convert Millimeters (mm) to Inches (in) instantly, or use the conversion table below to look up common values.
Millimeters to Inches conversion table
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 | 0.03937 |
| 2 | 0.07874 |
| 3 | 0.11811 |
| 4 | 0.15748 |
| 5 | 0.19685 |
| 10 | 0.393701 |
| 25 | 0.984252 |
| 50 | 1.968504 |
| 100 | 3.937008 |
How to convert Millimeters to Inches
1 mm equals 0.03937 in. Use the converter above for any value, or read the table for common conversions.
in = mm × 0.03937007874015748 · mm = in × 25.4Multiply a millimeters figure by 0.03937 to get inches, or divide it by 25.4 to go the other way.
Worked examples
- 1 mm= 0.03937 in
- 5 mm= 0.19685 in
- 10 mm= 0.393701 in
- 25 mm= 0.984252 in
- 100 mm= 3.937008 in
What these units are
Millimeters (mm). A millimeter is one thousandth of a meter. It is the unit for precision work — engineering tolerances, rainfall, wire gauges and the thickness of paper or sheet metal.
Inches (in). An inch is exactly 2.54 centimeters. It remains the standard unit for screen sizes, pipe and hose diameters, and tool sizes in imperial-measure countries.
Metric-to-metric conversions are exact. Imperial figures are exact by definition but are rounded for display, so a value converted back and forth can differ in the final digit.
Converting Millimeters to Inches in practice
Reading the result in inches
An inch is exactly 2.54 centimeters, or 25.4 millimeters. Twelve inches make one foot and thirty-six make a yard, so the inch sits inside two larger imperial units.
Screen and tyre sizes are given in inches, as are pipe and hose diameters, wrench openings and the diagonal of a television. Rainfall is still recorded in inches in some countries.
Because the inch has an exact metric value, converting to millimeters or centimeters introduces no error beyond display rounding. This site shows at most six decimal places, so very small fractions may appear shortened.
A frequent mistake is reading a pipe size as an exact outside diameter when trade sizes are nominal. Another is converting inches to centimeters and then labelling the answer millimeters.
People confuse inches with centimeters most often of all, then with feet. Screen and pipe sizes are inches, while fabric and body measurements may be either, and a twelvefold confusion between inches and feet is the usual consequence of misreading a unit label in practice.
Checking a millimeters to inches conversion
Inside the metric units every length conversion is a shift of the decimal point, so millimeters to centimeters, meters to kilometers and the rest can be done by moving it. Which way, and how far, follows from the prefix alone.
Converting between metric and imperial is not a shift but a single exact multiplication, and the factor is the same one for that pair however large or small the value. The trap is mixing the two systems halfway, as when a distance is stated in meters and inches in the same sentence.
To check a length conversion, run it backwards, or convert through a familiar middle value such as a meter or a foot. The one thing to keep straight is pairs that differ by a thousand rather than by ten, since those are where a misplaced decimal point survives unnoticed.
Tanzania reference points
Real quantities, converted into the units on this page.
Uhuru Peak on Mount Kilimanjaro, the highest point in Africa
5,895 m = 5,895,000 mm = 232,086.614173 in
The datasheet also records Kilimanjaro as rising 4,877 m above the surrounding plains.
Source: UNEP-WCMC World Heritage datasheet — Kilimanjaro National Park · verified 2026-09-14
Marangu Gate, the main road entrance to Kilimanjaro National Park
1,830 m = 1,830,000 mm = 72,047.244094 in
Source: UNEP-WCMC World Heritage datasheet — Kilimanjaro National Park · verified 2026-09-14
How far Mount Kilimanjaro rises above the plains around it
4,877 m = 4,877,000 mm = 192,007.874016 in
Source: UNEP-WCMC World Heritage datasheet — Kilimanjaro National Park · verified 2026-09-14
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