Player Efficiency Calculator
One box score in, three efficiency numbers out: Hollinger’s Game Score, the NBA’s official EFF, and per-36 production — benchmarked against real single-game tiers, with an honest note on why full PER needs league context.
Example: a 27-point line (10-of-19 shooting, 5-of-6 free throws, 8 rebounds, 7 assists, 1 steal, 1 block, 3 turnovers, 2 fouls in 36 minutes) → Game Score: 23.3.
- NBA efficiency (EFF)31
- Game Score per 3623.3
Computed by the calculator below using its default values. Change any input to see your own numbers.
How you compare
Your Game Score against typical NBA single-game tiers
Game Score, EFF, and where PER fits
John Hollinger built Game Score as the single-game cousin of his famous PER: one number that credits scoring efficiently, rebounding, playmaking, and defense, and debits missed shots, turnovers, and fouls. A rough map: 10 is an ordinary starter’s night, 20 is strong, 30 is a monster game, and the greatest scoring nights in modern history — like Kobe Bryant’s 81-point game — land in the 60s. EFF is the league’s simpler official tally (add the good, subtract the misses and turnovers). Full PER itself needs league-wide pace and efficiency context for the season, which is why a box-score calculator honestly cannot produce it — but Game Score tracks it closely game-to-game, and league-average PER is always set to 15.
Pair it with true shooting for the efficiency half of the story, or normalize a bench stat line with the per-36 output.
How it’s calculated
Game Score = PTS + 0.4×FGM − 0.7×FGA − 0.4×(FTA−FTM) + 0.7×ORB + 0.3×DRB + STL + 0.7×AST + 0.7×BLK − 0.4×PF − TOV (Hollinger). EFF = (PTS + REB + AST + STL + BLK) − (FGA−FGM) − (FTA−FTM) − TOV, the NBA’s official efficiency stat. Per-36 scales Game Score by minutes played.
Box-score measures — they cannot see screens, spacing, or defense beyond steals and blocks. Full PER additionally adjusts for league pace and is fixed to a league average of 15.
Worked example
The default line — 27 points on 10-of-19 and 5-of-6, 8 rebounds (2 offensive), 7 assists, a steal, a block, 3 turnovers, 2 fouls — scores 27 + 4 − 13.3 − 0.4 + 1.4 + 1.8 + 1 + 4.9 + 0.7 − 0.8 − 3 = 23.3: a clearly excellent night, short of monster status. Its EFF is (27+8+7+1+1) − 9 − 1 − 3 = 31.
Frequently asked questions
Is this the same as PER?
Game Score is PER's single-game cousin, built by the same analyst (John Hollinger) with similar weights — but full PER adjusts for league pace and efficiency across a whole season and is normalized so the league average is exactly 15. No box-score-only calculator can produce true PER; Game Score is the honest per-game equivalent.
What is a good Game Score?
Hollinger's own scale: about 10 is an average starter's game, 20 is strong, 30 is a monster night, 40 is historic. The highest modern Game Scores — Kobe Bryant's 81-point game, Luka Doncic's 60-point triple-double — land in the 60s.
What counts as a good PER for a season?
League average is fixed at 15 every season. Rotation players land in the 12-16 band, All-Stars typically 20+, MVP seasons usually 27+, and the all-time single-season marks sit just above 31.
What is the difference between Game Score and EFF?
EFF is the NBA's simple official tally: add points, rebounds, assists, steals, blocks, then subtract missed field goals, missed free throws, and turnovers — every event weighs 1. Game Score weights each event by its estimated point value (a missed shot costs 0.7, an assist earns 0.7), so it tracks true impact more closely.