Inches to millimeters converter, fractions included
Type 3/4, 1 1/2 or 0.375 and get millimeters. Or type millimeters and get the nearest 1/16, 1/32 or 1/64 inch. With a full fraction table.
Half of what I read is in fractions of an inch and the other half in millimeters. This converts both ways and rounds millimeters to the fraction a tape measure actually shows.
Fractions of an inch to millimeters
| Inches | Decimal inches | mm |
|---|---|---|
| 1/16" | 0.0625 | 1.588 |
| 1/8" | 0.125 | 3.175 |
| 3/16" | 0.1875 | 4.762 |
| 1/4" | 0.25 | 6.35 |
| 5/16" | 0.3125 | 7.938 |
| 3/8" | 0.375 | 9.525 |
| 7/16" | 0.4375 | 11.112 |
| 1/2" | 0.5 | 12.7 |
| 9/16" | 0.5625 | 14.288 |
| 5/8" | 0.625 | 15.875 |
| 11/16" | 0.6875 | 17.463 |
| 3/4" | 0.75 | 19.05 |
| 13/16" | 0.8125 | 20.638 |
| 7/8" | 0.875 | 22.225 |
| 15/16" | 0.9375 | 23.813 |
| 1" | 1 | 25.4 |
| 1 1/16" | 1.0625 | 26.987 |
| 1 1/8" | 1.125 | 28.575 |
| 1 3/16" | 1.1875 | 30.162 |
| 1 1/4" | 1.25 | 31.75 |
| 1 5/16" | 1.3125 | 33.338 |
| 1 3/8" | 1.375 | 34.925 |
| 1 7/16" | 1.4375 | 36.512 |
| 1 1/2" | 1.5 | 38.1 |
| 1 9/16" | 1.5625 | 39.688 |
| 1 5/8" | 1.625 | 41.275 |
| 1 11/16" | 1.6875 | 42.863 |
| 1 3/4" | 1.75 | 44.45 |
| 1 13/16" | 1.8125 | 46.037 |
| 1 7/8" | 1.875 | 47.625 |
| 1 15/16" | 1.9375 | 49.213 |
| 2" | 2 | 50.8 |
Everything is calculated in your browser. Nothing is saved or sent.
How it works
Since 1959 the inch is defined as exactly 25.4 mm.1 NIST lists the same factor, 2.54 × 10⁻² m.2 So millimeters = inches × 25.4, with no rounding in the factor itself.
For the other direction, the millimeters are divided by 25.4 and rounded to the nearest step you choose. The page shows how far that fraction is from your number, so you can see if 1/16 is close enough.
Common questions
How many mm is 3/4 inch?
19.05 mm. A sheet sold by a nominal size may not measure exactly that, so measure it before you cut a groove for it.
Is 19 mm the same as 3/4 inch?
Close but not equal: 3/4 inch is 19.05 mm. The 0.05 mm rarely matters in wood, but it adds up over many parts.