Millimeters to Inches Converter
Formula
inches = mm ÷ 25.4
To convert millimeters to inches, divide by 25.4. One inch equals exactly 25.4 millimeters.
How to use
- Type your length into the Millimeters field.
- The tool divides millimeters by 25.4 automatically.
- Read the converted length in the Inches result.
Example
Enter 25 in the Millimeters field. Dividing 25 by 25.4 gives about 0.9843 inches, just under 1 inch.
Frequently Asked Questions
How many inches is 25mm?
25mm equals approximately 0.9843 inches — just under 1 inch.
How many mm is 1 inch?
1 inch equals exactly 25.4 mm.
How do I convert a fraction of an inch to millimeters?
Multiply the decimal value of the fraction by 25.4. For example, 1/4 inch is 0.25, so 0.25 x 25.4 = 6.35 mm, and 1/2 inch equals 12.7 mm. This is handy when matching drill bits or hardware between imperial and metric sizes.
Why do some specs list both mm and inches?
Many products are designed in one measurement system but sold globally, so manufacturers print both to avoid confusion. A 16 mm phone bezel or a 10 mm wrench is the metric standard, while the inch equivalent helps buyers in the US visualize the size. Listing both also reduces returns caused by someone ordering the wrong size.