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How Does Duplicate Bridge Scoring Work?

Scoring is one of the parts of bridge that trips up newer players most. Rubber bridge and duplicate bridge use the same trick scores, but the bonus structure is completely different. In rubber bridge you build up a score over multiple deals. In duplicate, each board is scored completely on its own. That single change has a ripple effect through the whole strategy of the game.

What is the trick score in bridge?

The trick score is what you earn for each trick you bid and make, starting from the seventh trick (called Book). The rate depends entirely on the trump suit:

• Clubs and diamonds (the minor suits): 20 points per trick bid and made. So 3 Clubs making exactly scores 60 for the trick score alone.
• Hearts and spades (the major suits): 30 points per trick. Three Spades making exactly gives you 90.
• Notrump: 40 for the first trick (at the one level), then 30 for each additional trick. So 1NT scores 40, 2NT scores 70, 3NT scores 100.

When a contract is doubled, these scores are doubled. When redoubled, they are multiplied by four. That is why a doubled minor contract can become a game so quickly. Two Clubs doubled, making exactly, has a trick score of 80 (not 40), which does not reach game on its own. But three Clubs doubled gives 120 and is a game.

Overtricks made in an undoubled contract score the same rate as the trick score. Overtricks in a doubled contract score 100 per trick not vulnerable, or 200 vulnerable. Redoubled overtricks are 200 or 400 respectively.

How are game bonuses calculated in bridge?

A game bonus is awarded whenever the trick score for the contract reaches 100 or more. You do not need to bid a game for the trick score to qualify; a doubled partscore can reach 100 on the trick score and earn the game bonus. But in practice, the standard route to game is bidding and making 3NT, 4 Hearts, 4 Spades, 5 Clubs or 5 Diamonds.

The bonus amounts are:

• Not vulnerable game: 300 points
• Vulnerable game: 500 points
• Partscore (trick score under 100): 50 points only

This is where duplicate scoring diverges sharply from rubber bridge. In rubber bridge, you build toward game over several hands and earn a 700-point rubber bonus. In duplicate, every single board is independent. If you make a vulnerable game, you get 500 right now on that board, regardless of what happened before or what happens next. The result is that bidding and making a vulnerable game is always a huge swing, and failing to bid game when you can make it is one of the most costly errors in duplicate play.

A small slam (level 6) earns a slam bonus of 500 not vulnerable or 750 vulnerable, added on top of the game bonus and the trick score. A grand slam (level 7, all 13 tricks) earns 1000 not vulnerable or 1500 vulnerable. These are some of the biggest scores in the game, which is why slam bidding gets so much attention.

What happens when a contract is doubled?

Doubling has two very different effects depending on whether the contract is made or not.

If the contract is made after being doubled, the declarer earns the doubled trick score (which may or may not be enough to reach game), plus a flat 50-point insult bonus, sometimes called the "making bonus." Overtricks score 100 each (not vulnerable) or 200 each (vulnerable), which is often far more than the normal overtrick rate. This is why an overtrick in a doubled contract is so valuable; it shifts the score significantly compared to the same overtrick undoubled.

If the contract fails after being doubled, the penalties mount quickly. Not vulnerable, the first undertrick costs 100, the second and third each cost 200, and every subsequent undertrick costs 300. Vulnerable, the first undertrick costs 200, and the second, third and every subsequent undertrick cost 300. Redoubled penalties are exactly double those amounts.

The defender who doubles is essentially making a bet. If they are right and the contract fails, they collect a large penalty. If they are wrong and declarer makes it, they have handed the other side a bonus. Good duplicate players think carefully about when that bet is worth taking.