Metric Conversion Information

Confused about the metric system? Perhaps these tables can help. Jewelers the world over use the metric system for weights and measurements.

• Convert Inches to millimeters (mm)

• Convert millimeters (mm) to Inches

• Convert Inches to millimeters (mm)

  Inches		mm
  Fraction	Decimal
  1/1	1	25.4
  1/2	0.5	12.7
  1/4	0.25	6.35
  3/4	0.75	19.05
  1/5	0.2	5.08
  2/5	0.4	10.16
  4/5	0.8	20.32
  1/8	0.125	3.175
  3/8	0.375	9.525
  5/8	0.625	15.875
  7/8	0.875	22.225
  1/10	0.1	2.54
  3/10	0.3	7.62
  6/10	0.6	15.24
  7/10	0.7	17.78
  1/16	0.0625	1.5875
  3/16	0.1875	4.7625
  5/16	0.3125	7.9375
  7/16	0.4375	11.1125
  9/16	0.5625	14.2875
  11/16	0.6875	17.4625
  13/16	0.8125	20.6375
  15/16	0.9375	23.8125
  1/32	0.03125	0.79375
  3/32	0.09375	2.38125
  5/32	0.15625	3.96875
  7/32	0.21875	5.55625
  9/32	0.28125	7.14375
  11/32	0.34375	8.73125
  13/32	0.40625	10.31875
  15/32	0.46875	11.90625
  17/32	0.53125	13.49375
  19/32	0.59375	15.08125
  21/32	0.65625	16.66875
  23/32	0.71875	18.25625
  25/32	0.78125	19.84375
  27/32	0.84375	21.43125
  29/32	0.90625	23.01875
  31/32	0.96875	24.60625
  1/64	0.015625	0.396875
  3/64	0.046875	1.190625
  5/64	0.078125	1.984375
  7/64	0.109375	2.778125
  9/64	0.140625	3.571875
  11/64	0.171875	4.365625
  13/64	0.203125	5.159375
  15/64	0.234375	5.953125
  17/64	0.265625	6.746875
  19/64	0.296875	7.540625
  21/64	0.328125	8.334375
  23/64	0.359375	9.128125
  25/64	0.390625	9.921875
  27/64	0.421875	10.715625
  29/64	0.453125	11.509375
  31/64	0.484375	12.303125
  33/64	0.515625	13.096875
  35/64	0.546875	13.890625
  37/64	0.578125	14.684375
  39/64	0.609375	15.478125
  41/64	0.640625	16.271875
  43/64	0.671875	17.065625
  45/64	0.703125	17.859375
  47/64	0.734375	18.653125
  49/64	0.765625	19.446875
  51/64	0.796875	20.240625
  53/64	0.828125	21.034375
  55/64	0.859375	21.828125
  57/64	0.890625	22.621875
  59/64	0.921875	23.415625
  61/64	0.953125	24.209375
  63/64	0.984375	25.003125

• Convert millimeters (mm) to Inches

  mm	Inches
  	Decimal	Nearest Fraction
  0.1	0.003937008	1/256
  0.2	0.007874016	1/128
  0.3	0.011811024	3/256
  0.4	0.015748031	1/64
  0.5	0.019685039	3/128
  0.6	0.023622047	3/128
  0.7	0.027559055	7/256
  0.8	0.031496063	1/32
  0.9	0.035433071	9/256
  1	0.039370079	5/128
  1.3	0.051181102	13/256
  1.5	0.059055118	15/256
  1.7	0.066929134	17/256
  1.8	0.070866142	9/128
  2	0.078740157	5/64
  2.2	0.086614173	11/128
  2.4	0.094488189	3/32
  2.5	0.098425197	25/256
  2.7	0.106299213	27/256
  2.8	0.11023622	7/64
  3	0.118110236	15/128
  3.2	0.125984252	1/8
  3.4	0.133858268	17/128
  3.5	0.137795276	35/256
  3.8	0.149606299	19/128
  4	0.157480315	5/32
  4.1	0.161417323	41/256
  4.4	0.173228346	11/64
  4.5	0.177165354	23/128
  5	0.196850394	25/128
  5.5	0.216535433	55/256
  6	0.236220472	15/64
  6.5	0.255905512	33/128
  7	0.275590551	71/256
  7.5	0.295275591	19/64
  8	0.31496063	81/256
  8.5	0.334645669	43/128
  9	0.354330709	91/256
  9.5	0.374015748	3/8
  10	0.393700787	101/256
  10.5	0.413385827	53/128
  11	0.433070866	111/256
  11.5	0.452755906	29/64
  12	0.472440945	121/256
  12.5	0.492125984	63/128
  13	0.511811024	131/256
  13.5	0.531496063	17/32
  14	0.551181102	141/256
  14.5	0.570866142	73/128
  15	0.590551181	151/256
  16	0.62992126	161/256
  17	0.669291339	171/256
  18	0.708661417	181/256
  19	0.748031496	191/256
  20	0.787401575	101/128
  21	0.826771654	53/64
  22	0.866141732	111/128
  23	0.905511811	29/32
  24	0.94488189	121/128
  25	0.984251969	63/64
  25.4	1	1/1

Last updated December 7, 2007
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