For each contract points are earned for each trick won plus a bonus for a part-game or a game.
The game bonus is determined by what is called vulnerability. Vulnerability is set in advance for each deal. If vulnerable, a partnership wins a higher bonus for winning a game and higher penalties for failing to make their contract.
In some deals both sides are vulnerable, in other deals neither side is vulnerable or only one side.
Each trick is valued as follows:
Minor suits: 20 points
Majors suits: 30 points
Non trumps: 40 points for the first trick and 30 points for each additional trick
In addition to points for each trick the game bonus applies as follows:
A score of less than game = 50 points
A game score when not vulnerable = 300 points
A game score when vulnerable = 500 points
A small slam when not vulnerable = 800 points
A small slam when vulnerable = 1250 points
A slam when not vulnerable = 1300 points
A slam when vulnerable = 2000 points
By applying the trick points and the bonus each contract scores as follows:
Contract - NV, V
1 in a minor - 70 70
1 in a major - 80 80
1 in no trump - 90 90
2 in a minor - 90 90
2 in major - 110 110
2 in no trumps - 120 120
3 in a minor - 110 110
3 in a major - 140 140
3 no trumps - 400 600
4 in a minor - 130 130
4 in a major - 420 620
5 in a minor - 400 600
6 in a minor - 920 1370
6 in a major - 980 1430
6 in no trumps - 990 1440
7 in a minor - 1440 2140
7 in a major - 1510 2210
7 in no trumps - 1520 2220
For every extra trick over the contract, 20 points are in a minor suit and 30 points in a major suit and NT.
For every trick below the contract the declarer loses 50 points if not vulnerable and 100 if vulnerable. If the opposition believe the contract cannot be made they can increase the penalty by doubling the contract.
Result - NV, NVX, V, VX
one down - 50, 100, 100, 200
two down - 100, 200, 200, 500
three down - 150, 500, 300, 800
four down - 200, 800, 400, 1100
If your opponents have bid a contract with a good chance of success it is worth comparing their potential winning score with your score if you bid a contract that is likely to fail by only one or two tricks.
For example, if your opponents are vulnerable and bid 4H they would expect to win 620 points. If you are not vulnerable and have a good chance of making 8 tricks in spades then a contract of 4S will go down two. If your contract is doubled your opponents will win 500 points.
Going down by two tricks, is therefore, a better result than allowing your opponents to make their contract. This is called a sacrifice bid.
Taking the risk of a sacrifice bid is only worthwhile when your opponents are vulnerable and in a game contract and you are not vulnerable.