Trackball Ball Sizes and Replacement
Find Trackball Ball Size
First, find your trackball ball size at Trackball Reviews. For old trackball, check Trackball History
Ball Diameter Tolerance
Ball size differ by 1 or 2 mm is not a problem. More may be a problem.
76.2 mm Ball


76.2 mm and 57.15 mm Ball

(57.15 mm = 2 1/4 inch) American-style Billiard Ball
This set is highly recommended. The fuzzy coloring provides better tracking. Also lighter then normal billiard.


Aramith Premier Replacement Pool Ball Buy at amazon

Aramith Super Pro-Cup Pool Cue Ball 2.25 inch, 6 Red Dots Buy at amazon
55 mm Ball
Perixx 55 mm Ball Buy at amazon
52.388 mm (2 1/16 inch), Snooker ball
50 mm Ball

40 mm Ball

βK9 crystalβ is a type of high-tech glass. Light weight, and good optical property (example: no bubbles inside).
Note: it may not track well. I have not tried.
38.1 mm (1.5 inch) miniature pool ball
- DAD 5IVE Mini Billiards Pool Ball Set Buy at amazon
34 mm Ball


- Perixx 34 mm ball Buy at amazon
- Elecom 34 mm ball Buy at amazon

Crystal/Quartz Ball
Few things to be aware:
- Heavy ball may wear down the ceramic bearings in the trackball socket.
- Clear glass or polished surface may not track well.
- The advertised size is often inaccurate. Check buyer comments.
- May not be perfectly round.

Kensington Orbit Trackball with Scroll Ring, with Quartz Ball
Kensington Orbit Trackball with Scroll Ring



Inche to Millimeter Conversion Table
- 12 mm = 0.472 inch
- 13 mm = 0.512 inch
- 14 mm = 0.551 inch
- 15 mm = 0.591 inch
- 16 mm = 0.63 inch
- 17 mm = 0.669 inch
- 18 mm = 0.709 inch
- 19 mm = 0.748 inch
- 20 mm = 0.787 inch
- 21 mm = 0.827 inch
- 22 mm = 0.866 inch
- 23 mm = 0.906 inch
- 24 mm = 0.945 inch
- 25 mm = 0.984 inch
- 26 mm = 1.024 inch
- 27 mm = 1.063 inch
- 28 mm = 1.102 inch
- 29 mm = 1.142 inch
- 30 mm = 1.181 inch
- 31 mm = 1.22 inch
- 32 mm = 1.26 inch
- 33 mm = 1.299 inch
- 34 mm = 1.339 inch
- 35 mm = 1.378 inch (1 3/8 = 1.375)
- 36 mm = 1.417 inch
- 37 mm = 1.457 inch
- 38 mm = 1.496 inch
- 39 mm = 1.535 inch
- 40 mm = 1.575 inch
- 41 mm = 1.614 inch (1 5/8 = 1.625)
- 42 mm = 1.654 inch
- 43 mm = 1.693 inch
- 44 mm = 1.732 inch
- 45 mm = 1.772 inch
- 46 mm = 1.811 inch
- 47 mm = 1.85 inch
- 48 mm = 1.89 inch
- 49 mm = 1.929 inch
- 50 mm = 1.969 inch
- 51 mm = 2.008 inch
- 52 mm = 2.047 inch (52.388 mm = 2 1/16 inch)
- 53 mm = 2.087 inch
- 54 mm = 2.126 inch (53.975 mm = 2 1/8 inch)
- 55 mm = 2.165 inch
- 56 mm = 2.205 inch
- 57 mm = 2.244 inch (57 mm = 2 1/4 inch)
- 58 mm = 2.283 inch
- 59 mm = 2.323 inch