---
title: "Millimeters to Inches — mm to in converter"
description: "1 millimeter = 0.03937 inches. Convert millimeters to inches with a full conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/mm-to-inches/
site: "At One Place"
---

# Millimeters to inches

**1 millimeter in inches: 1 mm = 0.03937 in**

in = mm × 0.03937007874

To convert millimeters to inches, multiply by 0.03937007874. The table below gives the values people look up most often, and the converter works for any number.

## Millimeters to inches table

*Common millimeter values converted to inches.*

| Millimeters | Inches |
| --- | --- |
| 1 mm | 0.03937 |
| 2 mm | 0.07874 |
| 3 mm | 0.11811 |
| 4 mm | 0.15748 |
| 5 mm | 0.19685 |
| 10 mm | 0.3937 |
| 15 mm | 0.59055 |
| 20 mm | 0.7874 |
| 25 mm | 0.98425 |
| 30 mm | 1.181102 |
| 40 mm | 1.574803 |
| 50 mm | 1.968504 |
| 75 mm | 2.952756 |
| 100 mm | 3.937008 |
| 250 mm | 9.84252 |
| 500 mm | 19.68504 |
| 1,000 mm | 39.37008 |

## How the conversion works

The relationship is in = mm × 0.03937007874. Both units measure length, so the conversion is a fixed factor that never changes. The figure is exact rather than approximate: since the international yard and pound agreement of 1959, an inch is defined as exactly 25.4 millimetres and a pound as exactly 0.45359237 kilograms, and every other imperial and US customary unit here is derived from those two.

## Common questions

### How many inches are in one millimeter?

One millimeter equals 0.03937 inches. in = mm × 0.03937007874.

### How do you convert millimeters to inches?

Use in = mm × 0.03937007874. So 10 mm is 0.3937 in.

### How many millimeters are in one inch?

One inch equals 25.4 millimeters, which is the reverse of the conversion above.

## Related pages

- [Inches to Millimeters](https://atoneplace.net/convert/inches-to-mm/)
- [Millimeters to Meters](https://atoneplace.net/convert/mm-to-meters/)
- [Millimeters to Kilometers](https://atoneplace.net/convert/mm-to-km/)
- [Millimeters to Centimeters](https://atoneplace.net/convert/mm-to-cm/)
- [Millimeters to Miles](https://atoneplace.net/convert/mm-to-miles/)
- [Millimeters to Yards](https://atoneplace.net/convert/mm-to-yards/)
- [Millimeters to Feet](https://atoneplace.net/convert/mm-to-feet/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)