Inches to Millimeters Conversion
Convert any measurement instantly, or use the exact fractional and decimal charts below. 1 inch = 25.4 mm, exactly.
Full conversion charts
Exact values, computed at 1 in = 25.4 mm. Use the filter to jump to a value.
| Fraction | Decimal (in) | Millimeters |
|---|---|---|
| 1/16″ | 0.0625 | 1.587 |
| 1/8″ | 0.1250 | 3.175 |
| 3/16″ | 0.1875 | 4.762 |
| 1/4″ | 0.2500 | 6.350 |
| 5/16″ | 0.3125 | 7.938 |
| 3/8″ | 0.3750 | 9.525 |
| 7/16″ | 0.4375 | 11.112 |
| 1/2″ | 0.5000 | 12.700 |
| 9/16″ | 0.5625 | 14.287 |
| 5/8″ | 0.6250 | 15.875 |
| 11/16″ | 0.6875 | 17.462 |
| 3/4″ | 0.7500 | 19.050 |
| 13/16″ | 0.8125 | 20.637 |
| 7/8″ | 0.8750 | 22.225 |
| 15/16″ | 0.9375 | 23.813 |
| 1″ | 1.0000 | 25.400 |
| Decimal (in) | Millimeters |
|---|---|
| 0.001″ | 0.025 |
| 0.002″ | 0.051 |
| 0.003″ | 0.076 |
| 0.004″ | 0.102 |
| 0.005″ | 0.127 |
| 0.006″ | 0.152 |
| 0.007″ | 0.178 |
| 0.008″ | 0.203 |
| 0.009″ | 0.229 |
| 0.010″ | 0.254 |
| 0.020″ | 0.508 |
| 0.030″ | 0.762 |
| 0.040″ | 1.016 |
| 0.050″ | 1.270 |
| 0.060″ | 1.524 |
| 0.070″ | 1.778 |
| 0.080″ | 2.032 |
| 0.090″ | 2.286 |
| 0.100″ | 2.540 |
| 0.110″ | 2.794 |
| 0.120″ | 3.048 |
| 0.130″ | 3.302 |
| 0.140″ | 3.556 |
| 0.150″ | 3.810 |
| 0.160″ | 4.064 |
| 0.170″ | 4.318 |
| 0.180″ | 4.572 |
| 0.190″ | 4.826 |
| 0.200″ | 5.080 |
| 0.210″ | 5.334 |
| 0.220″ | 5.588 |
| 0.230″ | 5.842 |
| 0.240″ | 6.096 |
| 0.250″ | 6.350 |
| 0.260″ | 6.604 |
| 0.270″ | 6.858 |
| 0.280″ | 7.112 |
| 0.290″ | 7.366 |
| 0.300″ | 7.620 |
| 0.310″ | 7.874 |
| 0.320″ | 8.128 |
| 0.330″ | 8.382 |
| 0.340″ | 8.636 |
| 0.350″ | 8.890 |
| 0.360″ | 9.144 |
| 0.370″ | 9.398 |
| 0.380″ | 9.652 |
| 0.390″ | 9.906 |
| 0.400″ | 10.160 |
| 0.410″ | 10.414 |
| 0.420″ | 10.668 |
| 0.430″ | 10.922 |
| 0.440″ | 11.176 |
| 0.450″ | 11.430 |
| 0.460″ | 11.684 |
| 0.470″ | 11.938 |
| 0.480″ | 12.192 |
| 0.490″ | 12.446 |
| 0.500″ | 12.700 |
| 0.510″ | 12.954 |
| 0.520″ | 13.208 |
| 0.530″ | 13.462 |
| 0.540″ | 13.716 |
| 0.550″ | 13.970 |
| 0.560″ | 14.224 |
| 0.570″ | 14.478 |
| 0.580″ | 14.732 |
| 0.590″ | 14.986 |
| 0.600″ | 15.240 |
| 0.610″ | 15.494 |
| 0.620″ | 15.748 |
| 0.630″ | 16.002 |
| 0.640″ | 16.256 |
| 0.650″ | 16.510 |
| 0.660″ | 16.764 |
| 0.670″ | 17.018 |
| 0.680″ | 17.272 |
| 0.690″ | 17.526 |
| 0.700″ | 17.780 |
| 0.710″ | 18.034 |
| 0.720″ | 18.288 |
| 0.730″ | 18.542 |
| 0.740″ | 18.796 |
| 0.750″ | 19.050 |
| 0.760″ | 19.304 |
| 0.770″ | 19.558 |
| 0.780″ | 19.812 |
| 0.790″ | 20.066 |
| 0.800″ | 20.320 |
| 0.810″ | 20.574 |
| 0.820″ | 20.828 |
| 0.830″ | 21.082 |
| 0.840″ | 21.336 |
| 0.850″ | 21.590 |
| 0.860″ | 21.844 |
| 0.870″ | 22.098 |
| 0.880″ | 22.352 |
| 0.890″ | 22.606 |
| 0.900″ | 22.860 |
| 0.910″ | 23.114 |
| 0.920″ | 23.368 |
| 0.930″ | 23.622 |
| 0.940″ | 23.876 |
| 0.950″ | 24.130 |
| 0.960″ | 24.384 |
| 0.970″ | 24.638 |
| 0.980″ | 24.892 |
| 0.990″ | 25.146 |
| 1.000″ | 25.400 |
Worked examples
How to convert a compound dimension by hand using the charts.
Frequently asked questions
How many millimeters are in one inch?
One inch equals exactly 25.4 millimeters. The inch was defined as 25.4 mm by international agreement in 1959, so the conversion is exact, not rounded.
How do I convert inches to millimeters?
Multiply the inch value by 25.4. For example, 0.310 in × 25.4 = 7.874 mm. To go from millimeters back to inches, divide by 25.4.
How do I convert a fraction of an inch to millimeters?
Divide the fraction to get a decimal, then multiply by 25.4. For example, 17/64 = 0.265625 in, and 0.265625 × 25.4 = 6.747 mm. Or read it straight off the fractional chart above.
What is 0.120 inches in mm?
0.120 inches equals 3.048 millimeters.
Need this material cut to size?
NSRW stocks copper rounds, squares, and plate, and produces custom shapes and electrodes to your exact dimensions, in inches or millimeters.