How badminton scoring works
Badminton uses rally scoring: every rally is worth a point to whoever wins it, whether they served or not. That one sentence covers most of what people need, and the rest of this page is the detail that decides close games — the two-point rule, the cap that ends a deuce, and which service court you serve from.
Everything below matches what badmintho enforces on court, and the BWF laws are cited by number so you can check us.
A game is 21 points, won by two
First to 21 wins the game — but only with a lead of two clear points. At 20–20 nobody has won: play continues until one side is two ahead.
That is why a badminton score can pass 21. 22–20 is a normal result. So is 25–23.
The cap is a table, not a formula
A deuce cannot run forever, so each game length has a hard cap: at one point below it, the next rally simply wins. In a 21-point game the cap is 30 — at 29–29, the next point takes it 30–29, two-point rule or not (Law 7.5).
The part almost every explainer gets wrong: these caps are negotiated numbers, not the output of a rule you can compute. A 21-point game allows nine extra points; a 15-point game allows six. No arithmetic relation fits both, which is why it has to be a table:
| Game to | Two-point rule | Cap |
|---|---|---|
| 21 | yes | 30 — at 29–29 the next point wins |
| 15 | yes | 21 — at 20–20 the next point wins |
| 11 | no | none — first to 11, no deuce |
The 11-point game is the exception
The 11-point game drops the two-point rule entirely: its Law 7.2 omits the “except as provided in 7.4 and 7.5” qualifier that creates deuce in the longer formats. First to 11 wins, 11–10 is a result, and because there is no deuce there is nothing for a cap to bound.
This catches people out constantly, because the shorter format is what most clubs use for a quick round-robin.
Who serves, and from which side
The side that wins the rally serves the next one. Not the side that served last, and not alternating turns — winning the rally is what earns the serve. At the start of a new game, the winners of the previous game serve first.
The service court follows the serving side’s own score, and it is pure parity:
- Serving side’s score is even (0, 2, 4 …) — serve from the right court
- Serving side’s score is odd (1, 3, 5 …) — serve from the left court
That single rule is the one club players most often get wrong, and it is worth committing to memory: it never depends on the opponent’s score, on who served last, or on how many points ago you changed ends.
A worked example, from 20–20
Blue and Red are level at 20–20 in a 21-point game.
- Blue wins the rally: 21–20. Not a win — the lead is one.
- Red wins the next: 21–21. Level again.
- Red wins again: 22–21 to Red. Still one clear point.
- Red wins again: 23–21. Two clear points, so Red takes the game.
Had it run all the way to 29–29, the very next rally would have ended it at 30–29 regardless of the margin.
A match is best of three
A standard match is the best of three games — first to two. badmintho also offers best of one and best of five, where the number of games you need is simply more than half of them.
What badmintho does for you, and what it does not
badmintho keeps all of the above straight while you play, so nobody has to argue about it mid-match. It tracks serve rotation, the correct service court, game and match progression and the cap, and it carries your settings if your club plays a shorter format — you can set the game length to 3, 5, 7, 11, 15 or 21 points, switch the two-point rule on or off, and choose best of one, three or five.
What it does not do is decide who won the rally. There is no automatic point detection — you tap. Every app claiming otherwise is guessing from motion, and a wrong point is worse than a tap. Scoring by tapping is the only reliable way on a court, and it is what the watch app is built around.
Where these rules come from
BWF Statutes section 4.1, Laws of Badminton, Law 7 covers scoring: Law 7.5 sets the 29-all cap and Law 7.2 defines the game length. The shorter formats come from Part II section 1B Appendix 3, Other Scoring Systems, and the Alternative Laws of Badminton at section 4.1.4 come into force on 4 January 2027.
Rules summarised in plain English for players. Where this page and the BWF Statutes disagree, the Statutes are right — tell us at badmintho@red8.io and we will fix it.
More
The badmintho FAQ covers scoring on the watch, jump counting and match history. badmintho is free on the App Store for iPhone, Apple Watch and iPad.