This is my cheat sheet for doing international conversions.
Common Length and Distance Conversions
Fractional Inches to Decimal Inches and Metric Millimeters
Fraction to Decimal – Example
Convert 1/8″ to decimal:
- numerator is top number – numerator is 1
- denominator is bottom number – denominator is 8
- divide the top number with the bottom number – 1/8 = 0.125
The table below can be used to convert between fractional and/or decimal inches and metric millimeters.
Inches | Metric | |
Fractional | Decimal | mm |
. | 0.0039 | 0.1000 |
. | 0.0079 | 0.2000 |
. | 0.0118 | 0.3000 |
1/64 | 0.0156 | 0.3969 |
. | 0.0157 | 0.4000 |
. | 0.0197 | 0.5000 |
. | 0.0236 | 0.6000 |
. | 0.0276 | 0.7000 |
1/32 | 0.0313 | 0.7938 |
. | 0.0315 | 0.8000 |
. | 0.0354 | 0.9000 |
. | 0.0394 | 1.0000 |
. | 0.0433 | 1.1000 |
3/64 | 0.0469 | 1.1906 |
. | 0.0472 | 1.2000 |
. | 0.0512 | 1.3000 |
. | 0.0551 | 1.4000 |
. | 0.0591 | 1.5000 |
1/16 | 0.0625 | 1.5875 |
. | 0.0630 | 1.6000 |
. | 0.0669 | 1.7000 |
. | 0.0709 | 1.8000 |
. | 0.0748 | 1.9000 |
5/64 | 0.0781 | 1.9844 |
. | 0.0787 | 2.0000 |
. | 0.0827 | 2.1000 |
. | 0.0866 | 2.2000 |
. | 0.0906 | 2.3000 |
3/32 | 0.0938 | 2.3813 |
. | 0.0945 | 2.4000 |
. | 0.0984 | 2.5000 |
7/64 | 0.1094 | 2.7781 |
. | 0.1181 | 3.0000 |
1/8 | 0.1250 | 3.1750 |
. | 0.1378 | 3.5000 |
9/64 | 0.1406 | 3.5719 |
5/32 | 0.1563 | 3.9688 |
. | 0.1575 | 4.0000 |
11/64 | 0.1719 | 4.3656 |
. | 0.1772 | 4.5000 |
3/16 | 0.1875 | 4.7625 |
. | 0.1969 | 5.0000 |
13/64 | 0.2031 | 5.1594 |
. | 0.2165 | 5.5000 |
7/32 | 0.2188 | 5.5563 |
15/64 | 0.2344 | 5.9531 |
. | 0.2362 | 6.0000 |
1/4 | 0.2500 | 6.3500 |
. | 0.2559 | 6.5000 |
17/64 | 0.2656 | 6.7469 |
. | 0.2756 | 7.0000 |
9/32 | 0.2813 | 7.1438 |
. | 0.2953 | 7.5000 |
19/64 | 0.2969 | 7.5406 |
5/16 | 0.3125 | 7.9375 |
. | 0.3150 | 8.0000 |
21/64 | 0.3281 | 8.3344 |
. | 0.3346 | 8.5000 |
11/32 | 0.3438 | 8.7313 |
. | 0.3543 | 9.0000 |
23/64 | 0.3594 | 9.1281 |
. | 0.3740 | 9.5000 |
3/8 | 0.3750 | 9.5250 |
25/64 | 0.3906 | 9.9219 |
. | 0.3937 | 10.0000 |
13/32 | 0.4063 | 10.3188 |
. | 0.4134 | 10.5000 |
27/64 | 0.4219 | 10.7156 |
. | 0.4331 | 11.0000 |
7/16 | 0.4375 | 11.1125 |
. | 0.4528 | 11.5000 |
29/64 | 0.4531 | 11.5094 |
15/32 | 0.4688 | 11.9063 |
. | 0.4724 | 12.0000 |
31/64 | 0.4844 | 12.3031 |
. | 0.4921 | 12.5000 |
1/2 | 0.5000 | 12.7000 |
. | 0.5118 | 13.0000 |
33/64 | 0.5156 | 13.0969 |
17/32 | 0.5313 | 13.4938 |
. | 0.5315 | 13.5000 |
35/64 | 0.5469 | 13.8906 |
. | 0.5512 | 14.0000 |
9/16 | 0.5625 | 14.2875 |
. | 0.5709 | 14.5000 |
37/64 | 0.5781 | 14.6844 |
. | 0.5906 | 15.0000 |
19/32 | 0.5938 | 15.0813 |
39/64 | 0.6094 | 15.4781 |
. | 0.6102 | 15.5000 |
5/8 | 0.6250 | 15.8750 |
. | 0.6299 | 16.0000 |
41/64 | 0.6406 | 16.2719 |
. | 0.6496 | 16.5000 |
21/32 | 0.6563 | 16.6688 |
. | 0.6693 | 17.0000 |
43/64 | 0.6719 | 17.0656 |
11/16 | 0.6875 | 17.4625 |
. | 0.6890 | 17.5000 |
45/64 | 0.7031 | 17.8594 |
. | 0.7087 | 18.0000 |
23/32 | 0.7188 | 18.2563 |
. | 0.7283 | 18.5000 |
47/64 | 0.7344 | 18.6531 |
. | 0.7480 | 19.0000 |
3/4 | 0.7500 | 19.0500 |
49/64 | 0.7656 | 19.4469 |
. | 0.7677 | 19.5000 |
25/32 | 0.7813 | 19.8438 |
. | 0.7874 | 20.0000 |
51/64 | 0.7969 | 20.2406 |
. | 0.8071 | 20.5000 |
13/16 | 0.8125 | 20.6375 |
. | 0.8268 | 21.0000 |
53/64 | 0.8281 | 21.0344 |
27/32 | 0.8438 | 21.4313 |
. | 0.8465 | 21.5000 |
55/64 | 0.8594 | 21.8281 |
. | 0.8661 | 22.0000 |
7/8 | 0.8750 | 22.2250 |
. | 0.8858 | 22.5000 |
57/64 | 0.89063 | 22.6219 |
. | 0.9055 | 23.0000 |
29/32 | 0.90625 | 23.0188 |
59/64 | 0.92188 | 23.4156 |
. | 0.9252 | 23.5000 |
15/16 | 0.93750 | 23.8125 |
. | 0.9449 | 24.0000 |
61/64 | 0.95313 | 24.2094 |
. | 0.9646 | 24.5000 |
31/32 | 0.96875 | 24.6063 |
. | 0.9843 | 25.0000 |
63/64 | 0.98438 | 25.0031 |
1 | 1.000 | 25.40 |
. | 1.0039 | 25.5000 |
. | 1.0236 | 26.0000 |
. | 1.0433 | 26.5000 |
. | 1.0630 | 27.0000 |
. | 1.0827 | 27.5000 |
. | 1.1024 | 28.0000 |
. | 1.1220 | 28.5000 |
. | 1.1417 | 29.0000 |
. | 1.1614 | 29.5000 |
. | 1.1811 | 30.0000 |
. | 1.2205 | 31.0000 |
1 1/4 | 1.2500 | 31.7500 |
. | 1.2598 | 32.0000 |
. | 1.2992 | 33.0000 |
. | 1.3386 | 34.0000 |
. | 1.3780 | 35.0000 |
. | 1.4173 | 36.0000 |
. | 1.4567 | 37.0000 |
. | 1.4961 | 38.0000 |
1 1/2 | 1.5000 | 38.1000 |
. | 1.5354 | 39.0000 |
. | 1.5748 | 40.0000 |
. | 1.6142 | 41.0000 |
. | 1.6535 | 42.0000 |
. | 1.6929 | 43.0000 |
. | 1.7323 | 44.0000 |
1 3/4 | 1.7500 | 44.4500 |
. | 1.7717 | 45.0000 |
. | 1.8110 | 46.0000 |
. | 1.8504 | 47.0000 |
. | 1.8898 | 48.0000 |
. | 1.9291 | 49.0000 |
. | 1.9685 | 50.0000 |
2 | 2.0000 | 50.8000 |
. | 2.0079 | 51.0000 |
. | 2.0472 | 52.0000 |
. | 2.0866 | 53.0000 |
. | 2.1260 | 54.0000 |
. | 2.1654 | 55.0000 |
. | 2.2047 | 56.0000 |
. | 2.2441 | 57.0000 |
2 1/4 | 2.2500 | 57.1500 |
. | 2.2835 | 58.0000 |
. | 2.3228 | 59.0000 |
. | 2.3622 | 60.0000 |
. | 2.4016 | 61.0000 |
. | 2.4409 | 62.0000 |
. | 2.4803 | 63.0000 |
2 1/2 | 2.5000 | 63.5000 |
. | 2.5197 | 64.0000 |
. | 2.5591 | 65.0000 |
. | 2.5984 | 66.0000 |
. | 2.6378 | 67.0000 |
. | 2.6772 | 68.0000 |
. | 2.7165 | 69.0000 |
2 3/4 | 2.7500 | 69.8500 |
. | 2.7559 | 70.0000 |
. | 2.7953 | 71.0000 |
. | 2.8346 | 72.0000 |
. | 2.8740 | 73.0000 |
. | 2.9134 | 74.0000 |
. | 2.9528 | 75.0000 |
. | 2.9921 | 76.0000 |
3 | 3.0000 | 76.2000 |
. | 3.0315 | 77.0000 |
. | 3.0709 | 78.0000 |
. | 3.1102 | 79.0000 |
. | 3.1496 | 80.0000 |
. | 3.1890 | 81.0000 |
. | 3.2283 | 82.0000 |
. | 3.2677 | 83.0000 |
. | 3.3071 | 84.0000 |
. | 3.3465 | 85.0000 |
. | 3.3858 | 86.0000 |
. | 3.4252 | 87.0000 |
. | 3.4646 | 88.0000 |
3 1/2 | 3.5000 | 88.9000 |
. | 3.5039 | 89.0000 |
. | 3.5433 | 90.0000 |
. | 3.5827 | 91.0000 |
. | 3.6220 | 92.0000 |
. | 3.6614 | 93.0000 |
. | 3.7008 | 94.0000 |
. | 3.7402 | 95.0000 |
. | 3.7795 | 96.0000 |
. | 3.8189 | 97.0000 |
. | 3.8583 | 98.0000 |
. | 3.8976 | 99.0000 |
. | 3.9370 | 100.0000 |
4 | 4.0000 | 101.6000 |
. | 4.3307 | 110.0000 |
4 1/2 | 4.5000 | 114.3000 |
. | 4.7244 | 120.0000 |
5 | 5.0000 | 127.0000 |
. | 5.1181 | 130.0000 |
. | 5.5118 | 140.0000 |
. | 5.9055 | 150.0000 |
6 | 6.0000 | 152.4000 |
. | 6.2992 | 160.0000 |
. | 6.6929 | 170.0000 |
. | 7.0866 | 180.0000 |
. | 7.4803 | 190.0000 |
. | 7.8740 | 200.0000 |
8 | 8.0000 | 203.2000 |
. | 9.8425 | 250.0000 |
10 | 10.0000 | 254.0000 |
20 | 20.0000 | 508.0000 |
30 | 30.0000 | 762.0000 |
40 | 40.0000 | 1016.000 |
60 | 60.0000 | 1524.000 |
80 | 80.0000 | 2032.000 |
100 | 100.0000 | 2540.000 |