How to use it
- Type the points, field goals made and attempted, and free throws attempted from the box score.
- Type the three-pointers made. They are part of the field goals made.
- Read the Effective field goal % and the True shooting %, then open Working for each step.
The two shooting percentages
Effective field goal percentage corrects field goal percentage for threes: a made three is worth one and a half made twos, so it is counted with an extra half point.
True shooting percentage measures scoring efficiency from all shots: points divided by twice the true shooting attempts. In the formula a free throw attempt counts as 0.44 of a shot, the factor the glossary uses.
eFG% = (FG + 0.5 × 3P) / FGA
TS% = PTS / (2 × TSA)
TSA = FGA + 0.44 × FTAWhat this calculator does not cover
- EFF and PER: the calculator does not compute them, because no formula from an official source was confirmed for this page.
- Single games are noisy. A percentage over a whole season or a long run of games says more than one box score.
- The source defines the formulas; it does not say what a good value is for a position.
Worked example: 30 points on 22 shots
A player scores 30 points with 11 field goals made, 4 of them threes, from 22 attempts, and takes 6 free throws. The eFG% is (11 + 0.5 × 4) / 22 = 59.1 %.
The true shooting attempts are 22 + 0.44 × 6 = 24.64, so the TS% is 30 / (2 × 24.64) = 60.9 %.
| Measure | Value |
|---|---|
| Effective field goal % | 59.1 % |
| True shooting attempts | 24.64 |
| True shooting % | 60.9 % |
Frequently asked questions
Why does a three-pointer count more in eFG%?
A three is worth one point more than a two, so eFG% adds half a field goal for each three made. That lets it compare shooters who take many threes with those who take few.
Why is 0.44 used for free throws?
The Basketball-Reference glossary uses 0.44 as the free throw factor in true shooting attempts, to estimate how many field goal attempts a set of free throws is worth.
Can I use this calculator to compute PER or EFF?
No. The tool calculates effective field goal and true shooting percentages only. A formula for EFF from an official source was not confirmed, so the page leaves it out.
Which numbers do I need from the box score?
Points, field goals made and attempted, three-pointers made and free throws attempted. Those five totals give both percentages.
Why does the calculator show a dash?
A dash means there are no shots to divide by, for example a player who has not attempted a field goal or a free throw.
Sources
Figures and text last checked on Tuesday, November 10, 2026.