Darts averages, worked out

How a three-dart average turns into darts: what 501 takes at every average from 30 to 120, what nine darts leave, and why a real leg takes longer.

Last updated: 12 October 2026

A three-dart average is the number every darts player quotes, and it is plain arithmetic: points scored, divided by darts thrown, times three. This page works that arithmetic through a leg of 501, so the number means something at the board.

From darts to an average

Win a leg of 501 in 21 darts and your average for it is 71.57: 501 divided by 21, times three. Win it in 15 and the average is 100.2. Win it in nine and it is 167, the most a leg can have.

So a leg’s darts and its average are one fact, said two ways. Count the darts a leg took, and you have its average without a calculator anywhere near.

From an average to darts

Turn it round, and an average says how many darts 501 takes: 501 times three, divided by the average. At 60 it is 25 darts, at 80 about 19, and at 100 about 15.

The table below does this for every average from 30 to 120. It also says what is left after nine darts at that rate, which is where a leg usually turns from scoring to finishing.

Why a real leg takes longer

The table counts every dart as a scoring dart, and a real leg is not like that. Near the end the darts go at a double, and a dart that misses one scores little or nothing.

Say you score 60 a visit. After seven visits you have scored 420 and left 81. Take it out with T19 and D12, and the leg took 23 darts: an average of 65.35. Miss the double three times first, with darts that score nothing, and it took 26: an average of 57.81.

Same scoring, three darts more, and the average falls by more than seven points. That is why almost everyone has a first-nine average higher than their leg average.

The first nine

The first nine darts of a leg are scoring darts for nearly everyone: even at 120 a visit, nine darts leave 141. So the first-nine average is the scoring rate on its own, with the finishing left out.

At 60 a visit, nine darts leave 321; at 100, 201; at 120, 141, which is the classic last visit of a nine-darter.

Every nine-dart finish, counted →

Checkout percentage, worked out

Checkout percentage is legs finished, divided by the darts thrown at a double that would have finished them. Win four legs with 16 darts at a winning double and it is 25%.

It also says how long the end of a leg takes. At 25%, it takes four darts at a double, on average, to finish a leg; at 40%, two and a half.

Where the bot sits

The app’s bot plays at five levels, set to averages of 40, 55, 70, 85 and 100. Those are measured, not guessed: the bot’s legs are played through the same scorer as yours, and a test holds each level to its figure. The table marks where each one sits.

What each number means, and what counts as good →

The bot, and how it is calibrated →

Common questions

How is a three-dart average worked out?

Points scored, divided by darts thrown, times three. A leg of 501 won in 21 darts is 501 divided by 21, times three: 71.57.

What average wins a leg in 15 darts?

About 100: 501 divided by 15, times three, is 100.2. That is with every dart before the last one scoring and the double going in first time.

Why is my first-nine average higher than my average?

The first nine darts are all scoring darts. Later in the leg, darts go at the double, and a miss there scores little or nothing, which pulls the whole leg’s average down.

How is checkout percentage worked out?

Legs finished, divided by darts thrown at a double that would have finished them. Four legs from 16 darts at a winning double is 25%.