What the Basketball Effective Field Goal Percentage Calculator does
The Basketball Effective Field Goal Percentage Calculator estimates a shooting measure commonly shortened to eFG%. It adjusts field goal percentage to account for the additional point scored by a made three-pointer. The calculation uses three reader-supplied counts from one coherent box-score line: field goals made, three-point field goals made, and field goals attempted.
The calculator returns one percentage. It does not look up a game, check an official record, or confirm that the numbers belong to the same player, team, or period. You must provide internally consistent counts. Three-point makes are already included in total field goals made, and total makes cannot be greater than total attempts. The worksheet reports the arithmetic result without validating those relationships.
Unlike ordinary field goal percentage, eFG% gives extra weight to three-point makes. Because it measures scoring value relative to attempts, it can exceed 100%. If every attempt is a made three, the formula returns 150%. That result is valid for this measure and should not be clamped to 100% or read as ordinary shooting accuracy.
How to use the Basketball Effective Field Goal Percentage Calculator
- Choose the player, team, or other box-score line you want to examine, and use counts from the same period.
- Enter field goals made, counting both two-point and three-point baskets.
- Enter three-point field goals made. This count is part of the total field goals made, not an additional number to add to it.
- Enter field goals attempted. The calculator accepts at least one attempt because the formula divides by attempts.
- Read the effective field goal percentage, shown to two decimal places.
For the default example, enter 8 field goals made, 3 three-point field goals made, and 16 field goals attempted. The result is 59.38% when rounded to two decimal places. The unrounded result is 59.375%. These are counts, so they have no distance, time, or other measurement unit. The output is a percentage.
Before using a result in a comparison, check the original box score and confirm the scope. A player’s regular-season total, a single game, and a particular half are different samples. Counts from separate periods should not be combined unless you intend to calculate a combined rate and have combined attempts as well.
How the Basketball Effective Field Goal Percentage formula works
The formula is (field goals made + 0.5 × three-point field goals made) ÷ field goals attempted × 100. Each made field goal contributes one unit to the numerator. Each made three-pointer contributes an additional half unit, reflecting its extra point compared with a two-point make.
Using the default values, the calculation is (8 + 0.5 × 3) ÷ 16 × 100. First, half of 3 is 1.5. Add that to 8 to get 9.5. Divide 9.5 by 16, then multiply by 100. The result is 59.375%, displayed as 59.38% at two decimal places.
The inputs represent a coherent box-score line. In particular, three-point makes must be part of total field goals made. The number of three-point makes cannot exceed total makes, and total makes cannot exceed attempts. The calculator description states that it does not enforce these relationships, so check them yourself before relying on the output. Each input has a numerical range from 0 to 5,000, while attempts start at 1 to avoid division by zero.
Zero attempts have no defined eFG% under this formula. The calculator therefore requires at least one field goal attempt. If all 16 attempts in an example were made threes, the numerator would be 16 + 0.5 × 16, or 24. Dividing by 16 and multiplying by 100 gives 150%. This illustrates why the result is not capped at 100%.
Use cases for effective field goal percentage
eFG% can help summarize shooting efficiency when two-point and three-point makes are both part of the picture. A basic field goal percentage counts each make equally. eFG% adds a weighting for three-point makes, making it useful for a quick view of scoring value per field goal attempt.
- Reviewing a game: Calculate the measure from one player’s or team’s box-score counts for that game.
- Comparing periods: Calculate separate rates for separate periods, then review the attempts and context alongside each rate.
- Checking a season line: Use season totals for all three inputs, rather than mixing a season total with a single-game count.
- Learning the metric: Adjust the three-point makes input while holding other counts in mind to see how the extra weighting changes the result.
A single percentage cannot explain every part of a performance. It does not identify shot difficulty, defensive pressure, the circumstances of attempts, or how other scoring actions contributed. For a fair comparison, use consistent periods and scopes, and consult the underlying statistics when a small difference matters.
Other factors to consider when calculating eFG%
The quality of the input counts determines the usefulness of the calculation. Confirm that field goals made include all two-point and three-point makes, while the three-point count is only the subset made from beyond the arc. Confirm that attempts cover the same player or team and the same period. A mismatch can produce a precise-looking percentage that describes no real box-score line.
Keep eFG% distinct from ordinary field goal percentage. Ordinary percentage is field goals made divided by attempts, multiplied by 100. The eFG% formula adds half of the three-point makes before dividing. It is also distinct from measures that include free throws or broader possession estimates. Use the metric that matches the question you are trying to answer.
Rounding can create slight differences when comparing a displayed result with another source. This calculator displays two decimal places, while a box score or analytics page may use a different precision or aggregation method. Compare values at a consistent precision when practical, and retain the underlying counts if you need to reproduce the calculation.
Frequently asked questions
Can effective field goal percentage be greater than 100%?
Yes. If all field goal attempts are made three-pointers, the added half-credit makes the numerator 1.5 times the attempts, producing 150%. That is a valid eFG% result, not ordinary field goal accuracy.
Are three-point makes included in field goals made?
Yes. Field goals made is the total of two-point and three-point makes. Enter three-point makes separately as the subset used for the extra weighting. Do not add them to total makes a second time.
What happens when field goal attempts are zero?
The formula has no result for zero attempts because it would divide by zero. This calculator requires at least one field goal attempt.
Does this calculator verify a box score?
No. It calculates from the values you enter and does not retrieve or authenticate game records. Check the source and confirm that makes, three-point makes, attempts, and period belong together.
Where can I read about the NBA’s statistical formulas?
See the NBA Stats FAQ for its reference material on basketball statistics.