A handicap is a numerical measure of an amateur golfer's ability to play golf over 18 holes. The 2 main formulas used in the game are stroke play (also known as brutto or medal) and match play.
The Stroke play formula is an individual way of playing the game as you are competing against the par of the course by striking the ball the closest to the it. The Stroke play formula is simply the sum of strokes player shoot over 18 holes and compares it to the par (or the sum of a theoretical number of strokes per hole added up over 18 holes). The difference between your number of strokes and the par determines your handicap.
The match play formula is a game during which two players play against each other. In other words, your score per hole depends on the other player's score. This formula was - and still is - very much appreciated by golfers as the state of mind is totally different from a stroke play game, during which the golfer has to 'secure' each and single of his shots in order to play the lower score (number of strokes) possible over 18 holes. In the contrary, the match play rule will allow the player to approach the course in a more aggressive manner in order to win the hole against his opponent. e.g. P1 plays 4 and P2 plays 5: P1 wins the hole and current score on the tee number 2 would be '1 up'. If P2 would like to mention the status of the score, he would say: '1 down' (each player announces his position towards the game).
The so-called "net" score is a formula commonly preferred by players from different proficiency to play against each other on equal terms. Good Ones handicap is subtracted from their round score thus making a game even between two players. e.g. player 1's round score: 90 handicap: 20 / the course's par: 70 / Player 2's round score: 100 handicap: 30 overall (par): 70. a players handicap determines the quality of their game making a player with a lower handicap better than one with a higher handicap. However, in practice, motivated and ambitious high handicap players strive to lower their handicaps and thus the current official one they show on their cards might not be their real current level, which consequently might put them in a favourable position when playing 'net' formula games.
Handicaps are complicated, but essentially are the average over par of a number of previous rounds, adjusted for course difficulty. Legislations regarding the calculation of handicaps differs among countries and sometimes becomes so complicated that a golfer's handicap might not always mirror his real level of play. For example, Swiss handicap rules include the difficulty of the course the golfer is player on by taking into consideration factors such as the number of bunkers, the length of the course, the difficulty and slopes of the greens, the width of the fairways, and so on.
Handicap systems are not used in professional golf. Professional golfers typically score several strokes below par for a round thus have a handicap of 0 subtracting 0 from their round score.
