Free tool · Aiming
Cut angle & ghost ball calculator
Cut angle
20.4°
Thick cut
Ball overlap
65%
Of the object ball covered
Rolling deflection
32°
Cue ball with natural roll
Stun deflection
90°
Along the tangent line
What you see from behind the cue
What the numbers don't show
On a real table, cut shots are "thrown" slightly forward by friction between the balls — most at slow speed on thin-to-half-ball cuts. Experienced players overcut a touch to compensate. Side spin and cue-ball deflection change the line further.
The physics behind it
The object ball always leaves along the line from the contact point through its centre. So you aim the cue ball's centre at the ghost ball: one ball's width behind the object ball, on the line to the pocket. With a stun hit (no spin at contact), the cue ball leaves at 90° along the tangent line.
With natural roll it bends forward. Around a half-ball hit, that deflection is close to 30° — the well-known "30° rule". Learn to control it with the cue-ball control guides, plan kicks with the diamond system calculator, and drill it in the drill library.
Not sure where to start? Take the free skill test.