mm to Inches
Convert millimeters to inches.
Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.
Your result
How to convert millimeters to inches
1 mm = 0.03937 in. 1 inch is exactly 25.4 mm.
Formula: inches = millimeters ÷ 25.4
Examples
- 3 mm = 0.12 in
- 50 mm = 1.97 in
- 120 mm = 4.72 in
mm to in conversion table
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 mm | 0.0394 in |
| 2 mm | 0.0787 in |
| 3 mm | 0.1181 in |
| 4 mm | 0.1575 in |
| 5 mm | 0.1969 in |
| 6 mm | 0.2362 in |
| 8 mm | 0.315 in |
| 10 mm | 0.3937 in |
| 12 mm | 0.4724 in |
| 15 mm | 0.5906 in |
| 20 mm | 0.7874 in |
| 25 mm | 0.9843 in |
| 30 mm | 1.1811 in |
| 40 mm | 1.5748 in |
| 50 mm | 1.9685 in |
| 60 mm | 2.3622 in |
| 75 mm | 2.9528 in |
| 100 mm | 3.937 in |
| 150 mm | 5.9055 in |
| 200 mm | 7.874 in |
| 250 mm | 9.8425 in |
| 300 mm | 11.811 in |
Values are rounded to 4 decimal places.
How to use Mm to inches
- Enter the values you want to calculate and choose the relevant units or settings.
- The result updates as you type. Adjust the available settings if needed.
- Review the result, then use Copy result or a download link when available.
Useful next steps
How Mm to inches works
This converter turns millimeters into inches as you type. An inch is exactly 25.4 mm, so the tool divides your value by 25.4 and rounds the result to 12 significant digits. It accepts decimals, negative values and scientific notation such as 1e3. The answer is in decimal inches, which suits engineering drawings and drill or screw sizes, but it does not convert to fractions such as 1/8 inch or to feet and inches for you.
Before you start
Confirm your measurement is in millimeters and not centimeters, which differ by a factor of 10. Use a period as the decimal point.
A worked example
Entering 10 mm returns 0.393700787402 inches, and entering 25.4 mm returns exactly 1 inch.
Continue your workflow: Length, Weight, Temperature.
Common questions
How many millimeters are in an inch?
Exactly 25.4. The international inch is defined as 2.54 centimeters, which is 25.4 millimeters. To go from millimeters to inches, divide by 25.4. To go from inches to millimeters, multiply by 25.4.
How do I convert mm to a fraction of an inch?
Convert to decimal inches first, then multiply the decimal by the denominator you want and round. For 10 mm, the tool shows 0.3937 inches. 0.3937 × 16 is about 6.3, so 10 mm is close to 6/16, or 3/8 inch, and slightly larger.
Is 1 mm the same as 1/16 inch?
No. One millimeter is about 0.03937 inches, while 1/16 inch is 0.0625 inches, about 1.59 mm. A common mistake is treating the smallest marks on a metric ruler and an imperial ruler as equal. A sixteenth of an inch is over one and a half millimeters.
What is 1 mm in inches?
1 mm equals 0.0393700787402 inches in this converter, or about 0.04 inches. That is roughly 1/25 of an inch, so you need a little over 25 millimeters to make one inch.