The aim of badminton is to hit the shuttle with your racket so that it passes over the net and lands inside your opponent’s half of the court. Whenever you do this, you have won a rally; win enough rallies, and you win the match.
Your opponent has the same goal. He will try to reach the shuttle and send it back into your half of the court. You can also win rallies from your opponent’s mistakes: if he hits the shuttle into or under the net, or out of court, then you win the rally.
If you think your opponent’s shot is going to land out, then you should let it fall to the floor. If you hit the shuttle instead, then the rally continues.
Once the shuttle touches the ground, the rally is over. In this respect, badminton is not like tennis or squash, where the ball can bounce.
You must hit the shuttle once only before it goes over the net (even in doubles). In this respect, badminton is not like volleyball, where multiple players can touch the ball before sending it back over the net.
The shuttlecock (or shuttle) is a feathered (or plastic, mainly in un competitive games) projectile whose unique aerodynamic properties cause it to fly differently than the balls used in most rakquet sports; in particular, the feathers create much higher drag, causing the shuttlecock to decelerate more rapidly than a ball. Shuttlecocks have a much higher top speed, when compared to other racquet sports. Because shuttlecock flight is affected by wind, competitive badminton is played indoors. Badminton is also played outdoors as a casual recreational activity, often as a garden or beach game.
Since 1992, badminton has been an Olympic sport with five events: men's and women's singles, men's and women's doubles, and mixed doubles, in which each pair consists of a man and a woman. At high levels of play, especially in singles, the sport demands excellent fitness: players require aerobic stamina, agility, explosive strength, speed and precision. It is also a technical sport, requiring good motor coordination and the development of sophisticated racquet movements.
The court is rectangular and divided into halves by a net. Courts are usually marked for both singles and doubles play, although badminton rules permit a court to be marked for singles only. The doubles court is wider than the singles court, but both are of same length. The exception, which often causes confusion to newer players, is that the doubles court has a shorter serve-length dimension.
The full width of the court is 6.1 metres (20 ft), and in singles this width is reduced to 5.18 metres (17 ft). The full length of the court is 13.4 metres (44 ft). The service courts are marked by a centre line dividing the width of the court, by a short service line at a distance of 1.98 metres (6 ft 6 inch) from the net, and by the outer side and back boundaries. In doubles, the service court is also marked by a long service line, which is 0.76 metres (2 ft 6 inch) from the back boundary.
The net is 1.55 metres (5 ft 1 inch) high at the edges and 1.524 metres (5 ft) high in the centre. The net posts are placed over the doubles sidelines, even when singles is played.
The minimum height for the ceiling above the court is not mentioned in the Laws of Badminton. Nonetheless, a badminton court will not be suitable if the ceiling is likely to be hit on a high serve.
Badminton rules restrict the design and size of racquets and shuttlecocks. Badminton rules also provide for testing a shuttlecock for the correct speed:
To test a shuttlecock, use a full underhand stroke which makes contact with the shuttlecock over the back boundary line. The shuttlecock shall be hit at an upward angle and in a direction parallel to the side lines.
A shuttlecock of the correct speed will land not less than 530 mm and not more than 990 mm short of the other back boundary line.
Each game is played to 21 points, with players scoring a point whenever they win a rally regardless of whether they served  (this differs from the old system where players could only win a point on their serve and each game was played to 15 points). A match is the best of three games.
At the start of the rally, the server and receiver stand in diagonally opposite service courts (see court dimensions). The server hits the shuttlecock so that it would land in the receiver's service court. This is similar to tennis, except that a badminton serve must be hit below waist height and with the racquet shaft pointing downwards, the shuttlecock is not allowed to bounce and in badminton, the players stand inside their service courts unlike tennis.
When the serving side loses a rally, the serve immediately passes to their opponent(s) (this differs from the old system where sometimes the serve passes to the doubles partner for what is known as a "second serve").
In singles, the server stands in their right service court when their score is even, and in her/his left service court when her/his score is odd.
In doubles, if the serving side wins a rally, the same player continues to serve, but he/she changes service courts so that she/he serves to a different opponent each time. If the opponents win the rally and their new score is even, the player in the right service court serves; if odd, the player in the left service court serves. The players' service courts are determined by their positions at the start of the previous rally, not by where they were standing at the end of the rally. A consequence of this system is that, each time a side regains the service, the server will be the player who did not serve last time.
When the server serves, the shuttlecock must pass over the short service line on the opponents' court or it will count as a fault.
If the score reaches 20-all, then the game continues until one side gains a two point lead (such as 24–22), up to a maximum of 30 points (30–29 is a winning score).
At the start of a match, the shuttlecock is cast and the side towards which the shuttlecock is pointing serves first. Alternatively, a coin may be tossed, with the winners choosing whether to serve or receive first, or choosing which end of the court to occupy, and their opponents making the leftover the remaining choice.
In subsequent games, the winners of the previous game serve first. Matches are best out of three: a player or pair must win two games (of 21 points each) to win the match. For the first rally of any doubles game, the serving pair may decide who serves and the receiving pair may decide who receives. The players change ends at the start of the second game; if the match reaches a third game, they change ends both at the start of the game and when the leading player's or pair's score reaches 11 points.
The server and receiver must remain within their service courts, without touching the boundary lines, until the server strikes the shuttlecock. The other two players may stand wherever they wish, so long as they do not block the vision of the server or receiver.
If a let is called, the rally is stopped and replayed with no change to the score. Lets may occur because of some unexpected disturbance such as a shuttlecock landing on court (having been hit there by players on an adjacent court) or in small halls the shuttle may touch an overhead rail which can be classed as a let.
If the receiver is not ready when the service is delivered, a let shall be called; yet, if the receiver attempts to return the shuttlecock, he shall be judged to have been ready.
For Singles matches, the rules are:
-A match consists of best of 3 games.
-The side that first scored 21 points shall win.
-The side winning a rally shall add 1 point to its score.
-If a score becomes 20-20, the side which scores 2 consecutive points shall win that game.
-If the score becomes 29-29, the side that scores the 30th point shall win that game.
-The side winning a game serves first in the next game.
-When one side reaches 11 points, both players get a 60 second break.
-Both sides get a 2-minute break between first and second games, and another 2-minute break between second and third game.
-Other rules shall remain the same.
For Doubles matches, the rules are:
-One service only
-Back service line remains and the current rule applies.
The chart below explains the 3x21 rally point scoring system for doubles matches.
In a Doubles match between A&B against C&D. A&B win the toss and decide to serve. A will serve to C. A shall be the initial server while C shall be the initial receiver.