Technical documents

Steel Ball Size Chart

Unit: 1 inch = 25.4 mm

Name Diameter(mm) Name Diameter(mm) Name Diameter(mm)
0.3㎜ 0.3000 8.0㎜ 8.0000 1-1/8in 28.5750
0.4㎜ 0.4000 11/32in 8.7312 30.0㎜ 30.0000
0.5㎜ 0.5000 9.0㎜ 9.0000 1-3/16in 30.1625
0.6㎜ 0.6000 3/8in 9.5250 1-1/4in 31.7500
0.7㎜ 0.7000 10.0㎜ 10.0000 1-5/16in 33.3375
0.8㎜ 0.8000 13/32in 10.3188 1-3/8in 34.9250
1.0㎜ 1.0000 7/16in 11.1125 35.0㎜ 35.0000
1.2㎜ 1.2000 29/64in 11.5093 1-7/16in 36.5125
1.5㎜ 1.5000 15/32in 11.9062 1-1/2in 38.1000
1/16in 1.5875 12.0㎜ 12.0000 1-9/16in 39.6875
5/64in 1.9844 1/2in 12.7000 40.0㎜ 40.0000
2.0㎜ 2.0000 17/32in 13.4938 1-5/8in 41.2750
3/32in 2.3812 9/16in 14.2875 1-11/16in 42.8625
2.5㎜ 2.5000 15.0㎜ 15.0000 1-3/4in 44.4500
7/64in 2.7781 19/32in 15.0812 45.0㎜ 45.0000
3.0㎜ 3.0000 5/8in 15.8750 1-7/8in 47.6250
1/8in 3.1750 21/32in 16.6688 50.0㎜ 50.0000
3.5㎜ 3.5000 11/16in 17.4625 2in 50.8000
9/64in 3.5719 23/32in 18.2562 2-1/8in 53.9750
5/32in 3.9688 3/4in 19.0500 2-1/4in 57.1500
4.0㎜ 4.0000 25/32in 19.8437 60.0㎜ 60.0000
4.5㎜ 4.5000 20.0㎜ 20.0000 2-3/8in 60.3250
3/16in 4.7625 13/16in 20.6375 2-1/2in 63.5000
5.0㎜ 5.0000 27/32in 21.4312 2-3/4in 69.8500
7/32in 5.5562 7/8in 22.2250 3in 76.2000
15/64in 5.9531 29/32in 23.0188 80.0㎜ 80.0000
6.0㎜ 6.0000 15/16in 23.8125 3-1/4in 82.5500
1/4in 6.3500 31/32in 24.6063 3-1/2in 88.9000
17/64in 6.7469 25.0㎜ 25.0000 3-3/4in 95.2500
9/32in 7.1438 1in 25.4000 100.0㎜ 100.0000
5/16in 7.9375 1-1/16in 26.9875 4in 101.6000

*Some steel ball sizes are currently not in production. Depending on the material and size, we may also be able to produce sizes not listed in this chart. Please feel free to contact us via our contact form for details.
*For information on how steel balls are measured and related terminology, please refer to the JIS standard for steel balls.