Three Point Percentage Calculator (3P%)

Background.

Three-point percentage is made three-pointers divided by three-point attempts — Basketball-Reference and NBA.com's official glossary both give it as 3P / 3PA with no adjustments. What makes it worth its own calculator, rather than being just another shooting percentage, is that a three-point percentage is almost impossible to interpret on its own. A 36% shooter sounds mediocre next to a 50% two-point shooter, and is in fact producing more points per shot.

So alongside the percentage this calculator returns the two numbers that make the comparison honest. Points per attempt is simply three times your make rate: a 40% three-point shooter generates 1.20 points every time he lets one go. Break-even two-point percentage is 1.5 times your three-point percentage, and it answers the question directly — how good would a two-point shot have to be to be worth the same? For that 40% shooter the answer is 60%, which almost no shot outside the restricted area reaches.

This single piece of arithmetic explains the entire redesign of basketball offence since roughly 2010. The 2023-24 NBA league average was 36.6% from three, worth 1.098 points per attempt, against a league two-point percentage of 54.5%, worth 1.090. At league average the two shots are worth essentially the same — but the average two includes lay-ups and dunks, which means the mid-range jumper inside it is worth dramatically less. That is why the long two disappeared and why 39.5% of all NBA attempts in 2023-24 came from behind the arc.

One caveat on historical comparisons: the NBA has only had a three-point line since the 1979-80 season, and the line has been moved more than once, so 3P% is not comparable across those boundaries.

What is three point percentage calculator?

Three-point field goal percentage, written 3P%, is the share of three-point attempts a player or team converts: 3PM / 3PA. Basketball-Reference gives exactly that formula and notes the statistic is available in the NBA only from the 1979-80 season, when the three-point line was introduced; NBA.com's official glossary defines it as 'the percentage of 3 point field goal attempts that a player makes' with the formula (3PM)/(3PA). The statistic is a plain ratio with no coefficients or context terms. Its interpretation, however, requires context that the ratio itself does not supply, because a three-point make is worth 1.5 times a two-point make under NBA Rule 5. The natural way to restore that context is to convert the percentage into points per attempt by multiplying by three, and to compute the break-even two-point percentage by multiplying by 1.5 — that is the two-point conversion rate at which the two shots produce identical expected points. A three-point attempt is defined by where the shooter's feet are at the moment of release: a foot touching the line makes it a two-point attempt, so a shot that looks like a three from the stands may not be one in the box score. Note that 3P% says nothing about volume: a player who takes one three a week and makes 45% of them is not stretching a defence, while a high-volume 38% shooter is bending an entire scheme around himself.

How to use this calculator.

1. 01Enter made and attempted three-pointers for the span you are looking at — one game, a season, or a shooting session.
2. 02Remember that a shot with a foot on the line is scored as a two-point attempt and should not be counted here.
3. 03Read the percentage against the 2023-24 NBA average of 36.6%. Above 40% over a season is very good; above 43% is elite; below about 33% is a shot most coaches would rather you did not take unless the alternative is worse.
4. 04Use points per attempt when comparing against any other shot. It is three times the make rate, so 33% is 0.99 points, 36% is 1.08 and 40% is 1.20.
5. 05Use the break-even two-point percentage to settle the argument directly: it is the conversion rate a two-point shot would need to match your three. Compare it to the roughly 40% that a contested mid-range jumper actually converts at.

The formula.

The percentage is 3PM / 3PA. The two derived figures are what turn it into something you can act on.

Points per attempt. Every make is worth three points, so the expected value of a three-point attempt is 3 x the make rate. A 36% shooter produces 1.08 points per attempt; a 40% shooter produces 1.20; a 45% shooter produces 1.35. Expressing shooting in points per attempt rather than in percentages is the single easiest way to stop comparing incomparable numbers.

Break-even two-point percentage. A three at rate p3 yields 3 x p3 points. A two at rate p2 yields 2 x p2. Setting them equal gives 3 x p3 = 2 x p2, so p2 = 1.5 x p3. The break-even two-point percentage is therefore exactly one and a half times the three-point percentage — a 36% three-point shooter needs a 54% two-point shot to match, and a 40% shooter needs 60%. Once 3P% passes 66.7%, the break-even exceeds 100%, which is not an error: it correctly means no two-point shot of any kind can match that rate of three-point shooting.

Why this reshaped the sport. The 2023-24 NBA league averages were 36.6% from three and 54.5% from two, worth 1.098 and 1.090 points per attempt respectively — effectively identical. But the league two-point average is dragged upward by lay-ups and dunks converting near 65%, which means the mid-range jumper hiding inside that average converts nearer 40% and produces about 0.80 points per attempt. Against 1.098 for a league-average three, the long two is simply an inferior shot, and that is the entire arithmetic behind the disappearance of the mid-range game. In 2023-24, 39.5% of all NBA field goal attempts came from behind the arc.

Era caveat. The NBA had no three-point line before the 1979-80 season, and the distance has been changed more than once, including a shortened line from 1994-95 to 1996-97. The WNBA has had one since its 1997 inaugural season, NCAA men since 1986-87 and NCAA women since 1987-88, all at different distances from the NBA's. Three-point percentages are not comparable across those boundaries, and a college shooter's percentage routinely falls when he moves to the longer professional line.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Basketball-Reference.com Glossary, entry '3P%': "3-Point Field Goal Percentage (available since the 1979-80 season in the NBA); the formula is 3P / 3PA." The same entry is the source of the 1979-80 introduction date.
2. [2]NBA.com official Stats Glossary, entry '3 Point Field Goal Percentage': "The percentage of 3 point field goal attempts that a player makes. Formula (3PM)/(3PA)".
3. [3]NBA Official Rulebook, Rule 5 (Scoring and Timing) — a successful field goal attempted from beyond the three-point field goal line counts three points; all other successful field goals count two. This is the source of the 1.5 ratio behind the break-even calculation.
4. [4]Basketball-Reference.com, 2023-24 NBA player totals — Stephen Curry's season line of 357 three-pointers made from 876 attempts, used in the worked example.
5. [5]Basketball-Reference.com, 2023-24 NBA season summary — the League Average team row giving 1053 threes made from 2879 attempts (3P% .366), a two-point percentage of .545, and a three-point attempt rate of .395 of all field goal attempts.