NBA Efficiency Calculator
Calculated Efficiency Ratings
What Is an NBA Efficiency Calculator?
An NBA Efficiency Calculator measures a basketball player’s statistical performance using a weighted combination of positive and negative box score contributions. It calculates EFF from points, rebounds, assists, steals, blocks, missed shots, and turnovers. It also provides shooting efficiency percentages, Game Score, and a performance category based on EFF.
Unlike points scored alone, efficiency ratings consider several parts of a player’s performance. A player may score many points but also miss numerous shots or commit turnovers. Those negative contributions reduce the calculated efficiency rating.
This calculator provides four main result groups:
- NBA Efficiency (EFF): Combines positive box score contributions and subtracts missed shots and turnovers.
- Advanced Shooting Efficiency: Displays True Shooting Percentage (TS%) and Effective Field Goal Percentage (eFG%).
- Hollinger Game Score: Uses weighted box score statistics to estimate overall statistical production.
- Performance Breakdown: Assigns a performance category based on EFF and displays points, total rebounds, and assists.
The calculator supports both individual game statistics and season or multi-game totals. When using multiple games, the main efficiency rating and Game Score are divided by the number of games played.
How the NBA Efficiency Calculator Formulas Work
The calculator uses several mathematical formulas. Each measures a different aspect of a player’s box score performance.
1. NBA Efficiency Rating (EFF) Formula
NBA Efficiency Rating adds positive contributions and subtracts missed field goals, missed free throws, and turnovers.
Where:
- PTS: Points scored
- REB: Total rebounds (offensive plus defensive)
- AST: Assists
- STL: Steals
- BLK: Blocks
- FGA: Field goals attempted
- FGM: Field goals made
- FTA: Free throws attempted
- FTM: Free throws made
- TO: Turnovers
- GP: Games played
For a single game, GP equals 1. In season mode, the calculator divides the total efficiency score by the entered number of games played to produce EFF per game (EFF/G).
2. Effective Field Goal Percentage (eFG%) Formula
Effective Field Goal Percentage adjusts regular field goal percentage to recognize that a made three-pointer is worth more points than a made two-pointer.
Here, 3PM represents made three-point field goals. The additional 0.5 gives three-point makes extra weight when calculating shooting efficiency.
The calculator applies this formula when FGA is greater than zero. If there are no field goal attempts, it displays an eFG% of 0.0%.
3. True Shooting Percentage (TS%) Formula
True Shooting Percentage measures scoring efficiency by considering points scored, field goal attempts, and free throw attempts.
The calculator uses a 0.44 coefficient to estimate the possession cost associated with free throw attempts. This is a standard approximation within the formula, not a calculation of exact possessions used.
When the formula’s denominator is greater than zero, the calculator displays the resulting percentage. Otherwise, TS% is displayed as 0.0%.
4. Hollinger Game Score Formula
Game Score uses weighted box score statistics to summarize overall statistical production. Different actions contribute different amounts to the final score.
Additional variables include OREB for offensive rebounds, DREB for defensive rebounds, and PF for personal fouls.
For season or multi-game calculations, the calculator divides the total Game Score by games played:
In single-game mode, the Game Score is displayed without any multi-game averaging.
NBA Efficiency Calculation Example
Consider a hypothetical player with the following single-game statistics:
| Statistic | Value |
|---|---|
| Points (PTS) | 28 |
| Field Goals Made (FGM) | 10 |
| Field Goals Attempted (FGA) | 19 |
| 3-Point Field Goals Made (3PM) | 3 |
| Free Throws Made (FTM) | 5 |
| Free Throws Attempted (FTA) | 6 |
| Offensive Rebounds (OREB) | 2 |
| Defensive Rebounds (DREB) | 6 |
| Assists (AST) | 7 |
| Steals (STL) | 2 |
| Blocks (BLK) | 1 |
| Turnovers (TO) | 3 |
| Personal Fouls (PF) | 2 |
Step 1: Calculate total rebounds.
Step 2: Calculate missed shots.
Step 3: Calculate NBA Efficiency Rating.
Step 4: Calculate shooting efficiency.
Applying the Game Score formula gives 25.3.
The calculator displays these results:
- NBA Efficiency Rating: 33.0
- True Shooting Percentage: 64.7%
- Effective Field Goal Percentage: 60.5%
- Hollinger Game Score: 25.3
- Performance Category: Elite / MVP-Caliber Performance
The example uses hypothetical statistics. Its performance category comes from the calculator’s built-in efficiency thresholds, not an official NBA award or player ranking.
How to Use the NBA Efficiency Calculator
Follow these steps to calculate a player’s efficiency from box score statistics.
- Choose Calculation Scope. Select Single Game or Season / Multi-Game Totals.
- Enter Games Played if needed. In season mode, provide a positive number of games. The field is hidden in single-game mode.
- Enter scoring statistics. Fill in points, field goals made and attempted, three-pointers made, and free throws made and attempted.
- Enter rebounds and other statistics. Provide offensive rebounds, defensive rebounds, assists, steals, blocks, turnovers, and personal fouls.
- Click Calculate. The calculator generates the efficiency rating, shooting percentages, Game Score, and performance breakdown.
- Review the results. In season mode, EFF and Game Score are shown as per-game averages, while the shooting percentages use the combined totals.
- Click Reset to start over. This clears the entered statistics, hides the results, and restores Single Game mode.
Statistic fields use a minimum of zero and whole-number steps. Empty statistic fields are treated as zero during calculation. The calculator checks that made field goals do not exceed attempts, made three-pointers do not exceed made field goals, and made free throws do not exceed attempts.
All main numerical ratings and percentages are displayed to one decimal place. Enter accurate statistics to get meaningful results, because the calculator does not independently verify a box score.
How to Interpret Your NBA Efficiency Results
Each calculated metric provides a different perspective on a player’s statistical performance. Understanding these differences helps prevent misleading comparisons.
Understanding the EFF Performance Categories
The calculator assigns a performance category using the calculated EFF per game. In single-game mode, the single-game EFF is used because games played equals one.
| EFF or EFF/G | Calculator Performance Category |
|---|---|
| 30.0 or higher | Elite / MVP-Caliber Performance |
| 20.0 to below 30.0 | All-Star / Impact Starter Impact |
| 12.0 to below 20.0 | Solid Contributor / Standard Rotation |
| 5.0 to below 12.0 | Role Player / Reserve Level |
| Below 5.0 | Below Average / Low Impact Production |
These categories are labels defined in the calculator’s code. They are not official NBA classifications, and they do not establish whether a player qualifies for an award, starting position, or roster role.
The category depends only on EFF or EFF/G. True Shooting Percentage, Effective Field Goal Percentage, and Game Score do not change the assigned category.
EFF vs. Shooting Efficiency
EFF considers several box score contributions, including rebounding, assisting, defensive statistics, missed shots, and turnovers.
eFG% focuses on field goal shooting and gives extra weight to three-point makes. TS% measures scoring efficiency using total points and both field goal and free throw attempts.
As a result, two players can have similar EFF ratings but different shooting percentages. A player who contributes more rebounds, assists, or steals may offset a lower shooting efficiency in the EFF calculation.
What Game Score Adds
Game Score provides another weighted view of statistical production. Unlike the EFF formula, it applies different weights to offensive and defensive rebounds, assists, blocks, and other contributions.
It also subtracts a weighted amount for personal fouls. Personal fouls do not directly affect the EFF calculation used by this tool.
Single-Game vs. Season Efficiency
Single-game efficiency reflects one box score and can change substantially from game to game. Season efficiency uses accumulated statistics divided by games played, producing a per-game value.
In season mode, the calculator does not average individual game shooting percentages. It calculates TS% and eFG% directly from the entered season or multi-game totals.
The performance breakdown also shows total points, total rebounds, and total assists from the values entered, rather than dividing those three figures by games played.
No single box score metric fully describes defense, positioning, teamwork, opponent strength, or every contribution a player makes. Use these results as statistical summaries rather than complete judgments of player value.
Frequently Asked Questions
What is NBA Efficiency Rating (EFF)?
NBA Efficiency Rating is a box score statistic that combines points, rebounds, assists, steals, and blocks, then subtracts missed field goals, missed free throws, and turnovers. The calculator uses these contributions to produce a single-game EFF or a per-game average when multiple games are entered.
What is the difference between EFF and True Shooting Percentage?
EFF measures several types of box score production, while True Shooting Percentage focuses on scoring efficiency. TS% uses points scored, field goal attempts, and a weighted estimate of free throw attempts. A player can have a high TS% without having a similarly high EFF if other statistical contributions are limited.
How does the calculator determine EFF per game?
In Season / Multi-Game Totals mode, the calculator adds positive statistical contributions, subtracts missed shots and turnovers, and divides the resulting efficiency total by games played. The output is labeled NBA Efficiency Per Game (EFF/G). The games played input must be greater than zero.
Why does the calculator ask for three-pointers made?
Three-pointers made are used to calculate Effective Field Goal Percentage. The formula adds half the number of made three-pointers to total field goals made before dividing by field goal attempts. This accounts for the extra point scored on three-point field goals. The input does not directly enter the EFF formula.
What happens if a player has no field goal attempts?
If field goal attempts equal zero, the calculator displays an Effective Field Goal Percentage of 0.0%. True Shooting Percentage is also displayed as 0.0% if its entire denominator is zero. If the player has free throw attempts, TS% can still be calculated even with no field goal attempts.
Can NBA Efficiency Rating be negative?
Yes. EFF can be negative when missed shots and turnovers outweigh the player’s positive box score contributions. The calculator does not force negative efficiency results to zero. A result below 5.0 receives the tool’s lowest performance category, including negative values.
Is the NBA Efficiency Calculator an official NBA player ranking?
No. The calculator applies defined statistical formulas and its own performance thresholds to entered box score data. Although its formulas use established basketball statistics, the displayed categories are tool-defined descriptions. They do not represent official NBA player rankings, awards, or selections.