Duplicate Bridge Score Calculator
Calculate the score for a single contract in duplicate bridge (declarer-side perspective).
What this bridge calculator does
This bridge calculator computes the score for one contract in duplicate bridge. It handles contract points, overtricks, undertrick penalties, partscore/game bonuses, slam bonuses, and doubled/redoubled insult bonuses.
If you're reviewing hands, teaching new players, or checking score accuracy after a club game, this is a fast way to verify the math.
How duplicate bridge scoring works
1) Contract requirement
A contract at level N requires N + 6 tricks. Example: 4♥ requires 10 tricks.
2) Contract trick values
| Strain | Undoubled trick value | Notes |
|---|---|---|
| Clubs / Diamonds (Minors) | 20 per trick bid | Lower trick value; game often needs level 5 |
| Hearts / Spades (Majors) | 30 per trick bid | Game typically at level 4 |
| No Trump | 40 first trick + 30 each additional | Game often at 3NT |
3) Bonuses and penalties
- Partscore bonus: +50 if contract points are below 100.
- Game bonus: +300 non-vulnerable or +500 vulnerable when contract points are 100+.
- Small slam (level 6): +500 non-vulnerable, +750 vulnerable.
- Grand slam (level 7): +1000 non-vulnerable, +1500 vulnerable.
- Insult bonus: +50 doubled or +100 redoubled (if made).
- Undertricks: penalized more harshly when doubled/redoubled, especially vulnerable.
Why vulnerability matters so much
Vulnerability increases both reward and risk. You gain larger game/slam bonuses when vulnerable, but you also pay heavier undertrick penalties. That tradeoff drives many bidding decisions: whether to push to game, sacrifice, or double aggressively.
Quick usage examples
Example A: 4♥ making exactly, non-vulnerable, undoubled
- Contract points: 4 × 30 = 120
- Game bonus: +300 (non-vulnerable)
- Total: 420
Example B: 3NT +1, vulnerable, undoubled
- Contract points: 40 + 30 + 30 = 100
- Overtrick: +30
- Game bonus: +500
- Total: 630
Example C: 4♠ doubled down 2, non-vulnerable
- Undertrick penalties: 100 + 200 = 300
- Total: -300 (from declarer perspective)
Tips for accurate scoring
- Always confirm whether the declarer side is vulnerable.
- Score from one side’s perspective (this tool uses declarer-side perspective).
- Separate contract points from bonuses; game eligibility depends on contract points only.
- For doubled contracts, remember the insult bonus applies only when the contract makes.
Frequently asked questions
Does this calculator include IMPs or matchpoints?
No. It calculates raw duplicate score for a single board. IMP conversion and matchpoint ranking are separate steps.
Is this rubber bridge scoring?
No. This is duplicate bridge style scoring, which is what most club and tournament sessions use.
Can I use this for teaching beginners?
Yes. The score breakdown makes it easy to show where points come from and why bidding decisions matter.