About the Basketball Efficiency Calculator
This basketball efficiency calculator turns a single box score line into the all-in-one numbers analysts quote: the NBA efficiency rating (EFF), John Hollinger’s Game Score, true shooting percentage (TS%) and effective field goal percentage (eFG%). It also scales efficiency to 36 minutes so bench players and starters can be compared fairly.
Enter points, made and attempted field goals, three-pointers and free throws, offensive and defensive rebounds, assists, steals, blocks, turnovers and personal fouls. It suits coaches grading players after a game, fantasy managers, and fans who want to know whether a 30-point night was efficient or just high-volume.
A note on PER: the true Player Efficiency Rating needs league-wide pace and team totals, so it cannot be computed from one box score. EFF and Game Score are the box-score cousins of PER and are designed for exactly this kind of quick, single-game evaluation.
With the default inputs, the efficiency (eff) is 31. Change any value above to recalculate instantly.
How to use the basketball efficiency calculator
- 1Copy the player’s points and shooting numbers from the box score.
- 2Enter offensive and defensive rebounds separately.
- 3Add assists, steals, blocks, turnovers and fouls.
- 4Enter minutes played for the per-36 figure.
- 5Compare EFF, Game Score and true shooting to judge the performance.
Formula and method
EFF, the efficiency formula long used by the NBA and FIBA box scores, simply adds every positive counting stat and subtracts missed shots and turnovers, each weighted equally. Game Score, devised by John Hollinger, weights each stat by its estimated value, so a missed shot costs less than a turnover and offensive rebounds count more than defensive ones; its scale is similar to points scored.
True shooting percentage is PTS ÷ (2 × (FGA + 0.44 × FTA)), which folds threes and free throws into one efficiency figure; the 0.44 factor approximates the share of free throws that end a possession. Effective FG% gives a made three 1.5 times the value of a two: (FGM + 0.5 × 3PM) ÷ FGA.
- PTS
- Points scored
- FGM / FGA
- Field goals made / attempted
- FTM / FTA
- Free throws made / attempted
- ORB / DRB / REB
- Offensive, defensive and total rebounds
- AST, STL, BLK, TOV, PF
- Assists, steals, blocks, turnovers, personal fouls
Worked examples
Strong starter: 28 points on 10-of-20
EFF = 28 + 8 + 6 + 2 + 1 = 45 positives, minus 10 missed field goals, 1 missed free throw and 3 turnovers = 31. Game Score = 28 + 4 − 14 − 0.4 + 1.4 + 1.8 + 2 + 4.2 + 0.7 − 0.8 − 3 = 23.9. True shooting is 28 ÷ (2 × (20 + 0.44 × 6)) = 61.8%.
Big man: 12 pts, 15 reb, 4 blk in 30 min
EFF = 12 + 15 + 2 + 1 + 4 − 4 − 2 − 2 = 26, or 26 × 36 ÷ 30 = 31.2 per 36 minutes. Game Score = 12 + 2 − 6.3 − 0.8 + 3.5 + 3 + 1 + 1.4 + 2.8 − 1.6 − 2 = 15.0, a solid game, and TS% is 12 ÷ (2 × 10.76) = 55.8%.
Frequently asked questions
What is the NBA efficiency (EFF) formula?+
EFF = points + rebounds + assists + steals + blocks − missed field goals − missed free throws − turnovers. Every stat counts as one point, which makes it simple but favours high-volume players.
What is a good Game Score?+
Hollinger designed Game Score on a scale like points: about 10 is an average game, 20 is very good, 30 is excellent and 40 or more is one of the best games of a season.
Can I calculate PER from one box score?+
Not exactly. Player Efficiency Rating adjusts for team pace, league averages and the value of a possession, which needs season-wide league data. EFF and Game Score are single-game approximations.
What is true shooting percentage?+
True shooting measures scoring efficiency including threes and free throws: points ÷ (2 × (FGA + 0.44 × FTA)). The NBA average has been around 57–58% in recent seasons.
What is the difference between eFG% and TS%?+
Effective field goal percentage credits three-pointers with 1.5 times the value of a two but ignores free throws. True shooting includes free throws as well, so it is the fuller measure of scoring efficiency.