Dartboard anatomy: scoring areas, number order and sizes

You look at it every time you throw, but do you know why the 20 is wedged between the 5 and the 1, or exactly what that little red circle in the middle is worth? Here's the standard dartboard, area by area, with its measurements and a bit of its history.

The scoring areas

The board is split into 20 segments numbered 1 to 20, each covering 18°. Each segment is divided into areas that score differently.

A few numbers that follow from that:

• the best single dart is treble 20, worth 60;
• three treble 20s make 180, the maximum for a visit;
• the bullseye counts as a double: that's what lets you check out 170 in three darts (treble 20, treble 20, bull), the biggest possible finish under double out.

The colours

The segments alternate black and white (usually cream). The double and treble rings alternate red and green. In the middle, the 25 is green and the 50 is red. The colours are only there to make the board easy to read; they make no difference to the score.

The measurements

A standard bristle board is 451 mm in diameter overall. Not all of that counts, though: the scoring area stops at the outer edge of the double ring, 170 mm from the centre. Beyond that is the black outer band that holds the number ring, and a dart landing there scores nothing.

The 8 mm of the doubles and trebles is measured inside the wires. Aiming for a treble means aiming for a band barely wider than a fingernail, from 2.37 m away. The wires themselves make up the spider, and a dart never lands "in" a wire: it always falls on one side or the other.

The number order

Starting at the top and going clockwise:

20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7, 16, 8, 11, 14, 9, 12, 5

The 20 sits at the top, centred (it spans 9° either side of vertical). The 3 is at the bottom, the 6 on the right and the 11 on the left.

Why that order?

It's anything but random: the layout is designed to punish inaccuracy. The big numbers are nearly always flanked by small ones:

• the 20 sits between the 5 and the 1: just miss treble 20 and you score 5 or 1 instead;
• the 19 sits between the 7 and the 3;
• the 17 sits between the 2 and the 3;
• the 16 sits between the 7 and the 8.

If the numbers simply ran from 1 to 20, the big ones (17, 18, 19, 20) would all sit together: aim at that corner of the board and you'd score heavily even with a sloppy throw, and the game would lose all its tension. On the real board, every centimetre counts.

It's also why some players prefer to go for treble 19: its neighbours (7 and 3) are a little more forgiving than the 20's (5 and 1). More on that in how to hit treble 20.

A little history

Legend has it that the order was devised by Brian Gamlin, a carpenter from Lancashire, in the late 19th century (1896 is the date usually quoted). It's a nice story, but it can't be verified and is often disputed by darts historians, and other names have been put forward. What is certain is that this layout, sometimes called the "London" or "clock" board, eventually took over everywhere.

Other regional English boards still exist, with different layouts, and some don't even have a treble ring. But every competition and every common game is played on the standard board described here.

Know your board, play better

Knowing what surrounds each number changes how you play: in cricket, in Halve It or when setting up a finish in 501, picking a target that forgives a miss can save a visit. And if you'd rather not do the maths yourself, Throw does it for you: a phone stood off to the side works out where each dart lands on these very areas and keeps score on its own.

For the rest of the vocabulary (oche, spider, ton, bust...), head to the darts glossary.