An undertrick penalty is what the defenders score for each trick declarer falls short of the contract. Undoubled, each undertrick costs 50 not vulnerable or 100 vulnerable; doubled, the penalty starts at 100 or 200 and grows with every extra trick down.
The strain does not matter: one down in 2♣ costs the same as one down in 7NT. Only vulnerability and doubling change the penalty.
Undertrick Penalty Table
Total penalty for going down, by number of undertricks:
| Down | Not vul | Not vul, X | Not vul, XX | Vul | Vul, X | Vul, XX |
|---|---|---|---|---|---|---|
| 1 | 50 | 100 | 200 | 100 | 200 | 400 |
| 2 | 100 | 300 | 600 | 200 | 500 | 1000 |
| 3 | 150 | 500 | 1000 | 300 | 800 | 1600 |
| 4 | 200 | 800 | 1600 | 400 | 1100 | 2200 |
| 5 | 250 | 1100 | 2200 | 500 | 1400 | 2800 |
| 6 | 300 | 1400 | 2800 | 600 | 1700 | 3400 |
| 7 | 350 | 1700 | 3400 | 700 | 2000 | 4000 |
X means doubled and XX redoubled. These numbers are the same in duplicate, Chicago and rubber bridge.
How Doubled Penalties Grow
Undoubled penalties grow evenly. Doubled ones speed up:
- Not vulnerable, doubled: 100 for the first undertrick, 200 each for the second and third, 300 each from the fourth on.
- Vulnerable, doubled: 200 for the first, 300 for each one after.
- Redoubled: twice the doubled amounts.
So the step from two down to three down doubled not vulnerable costs another 200, and from three to four, 300. A sacrifice that you expect to go down three can turn into a disaster if it goes down four.
Sacrifices and Penalty Doubles
A sacrifice is a contract you bid expecting to go down, because the penalty costs less than the opponents' contract. Compare with what they would score:
Favorable vulnerability: East-West are vulnerable, you are not. You overcall 1♠, and partner sacrifices in 4♠ over their 4♥. You are declarer.
East-West are vulnerable, and their 4♥ would score 620. Your 4♠ doubled costs 300 two down or 500 three down, both less than 620. Four down (800) is too much. That is why sacrifices are most attractive at favorable vulnerability (you not vulnerable, they vulnerable) and rarely right at unfavorable.
A penalty double works the other way. When the opponents stretch into a part score, doubling can collect more than your own contract would score. Two down doubled vulnerable is 500, more than any part score you could make and close to a game. At matchpoints, defenders who expect to beat a contract two tricks often double for that reason.
How far down can a sacrifice against a major-suit game go and still gain?
| Vulnerability (you / them) | Their game | Still cheaper | Too expensive |
|---|---|---|---|
| Not vul / vul (favorable) | 620 | 3 down X (500) | 4 down X (800) |
| Not vul / not vul | 420 | 2 down X (300) | 3 down X (500) |
| Vul / vul | 620 | 2 down X (500) | 3 down X (800) |
| Vul / not vul (unfavorable) | 420 | 1 down X (200) | 2 down X (500) |
Rule of ThumbBefore you sacrifice, compare: the opponents' game (420 or 620, more for a slam) against your expected penalty. If you are not sure they make their contract, do not sacrifice.
Practice: Undertrick Penalties
You are vulnerable and play 3♠ doubled. You take six tricks. What do the defenders score?
For the plus side of the score, see bridge scoring and the bridge scoring chart. Competitive decisions like these are the theme of the Law of Total Tricks. BridgeDummy's bidding puzzles let you test a sacrifice decision: the hidden hands are dealt many times, and every call is solved double dummy.