Inches to Millimeters
Type a value in in and get mm instantly: 1 in = 25.4 mm
1 in = 25.4 mm
⇄ Millimeter → InchThe conversion between inches (in) and millimeters (mm) is fixed: 1 in = 25.4 mm and 1 mm = 0.0394 in. To convert in to mm, multiply by 25.4; to go the other way, multiply by 0.0394 (or divide by 25.4). For example, 2 in = 50.8 mm and 12 in = 304.8 mm.
Enter any value in the converter above; the result updates as you type. You will also find a ready-made table for common values, the formula, and a link to the reverse conversion (millimeters to inches).
One inch is exactly 25.4 mm. Drill bits, bolts and pipes are often sized in fractions of an inch: 1/4 in = 6.35 mm, 1/2 in = 12.7 mm, 3/4 in = 19.05 mm.
Quick answers
Inches to Millimeters conversion table
| Inches (in) | Millimeters (mm) |
|---|---|
| 0.125 in | 3.175 mm |
| 0.25 in | 6.35 mm |
| 0.375 in | 9.525 mm |
| 0.5 in | 12.7 mm |
| 0.625 in | 15.875 mm |
| 0.75 in | 19.05 mm |
| 1 in | 25.4 mm |
| 1.5 in | 38.1 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 8 in | 203.2 mm |
| 10 in | 254 mm |
| 12 in | 304.8 mm |
| 18 in | 457.2 mm |
| 24 in | 609.6 mm |
| 36 in | 914.4 mm |
Millimeters to Inches quick table
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 mm | 0.0394 in |
| 4 mm | 0.1575 in |
| 6 mm | 0.2362 in |
| 12 mm | 0.4724 in |
| 20 mm | 0.7874 in |
| 40 mm | 1.5748 in |
| 60 mm | 2.3622 in |
| 150 mm | 5.9055 in |
| 250 mm | 9.8425 in |
| 1,000 mm | 39.37 in |
Frequently Asked Questions
How many millimeters are in 1 Inch?
1 in = 25.4 mm. Multiply a value in in by 25.4 to get mm.
How do I convert millimeters to inches?
Multiply the value in mm by 0.0394, or divide it by 25.4. For example, 50.8 mm ≈ 2 in.
What is 12 in in mm?
12 in = 304.8 mm.
Is the factor 25.4 exact?
Both units have exact international definitions, so the factor is fixed; only the displayed value is rounded.