Why Duplicate Scoring Matters
Duplicate bridge score calculation rewards precision, not luck. Each board is compared with results from other tables. A small overtrick can beat many pairs. A safe part score can also win when game fails elsewhere.
This calculator follows standard contract scoring. It separates the contract result from comparison scoring. First, it scores the declared contract. Then it converts that result to North-South perspective. Finally, it can compare your score against other table scores for matchpoints and IMPs.
Core Scoring Ideas
Bridge scoring starts with contract trick points. Minor suits score twenty points per contracted trick. Major suits score thirty points per contracted trick. Notrump gives forty points for the first trick above book. Each later notrump trick scores thirty points. Doubled and redoubled contracts multiply only the contract trick value before game status is tested.
Bonuses shape the final score. A made part score receives fifty points. A made game receives three hundred when not vulnerable, or five hundred when vulnerable. Small slams add five hundred not vulnerable, or seven hundred fifty vulnerable. Grand slams add one thousand not vulnerable, or fifteen hundred vulnerable. Doubled and redoubled made contracts also receive insult bonuses.
Advanced Comparison Use
Duplicate events often use matchpoints or IMPs. Matchpoints rank one score against all other scores on the same board. You earn two matchpoints for every lower score and one for every tie. The maximum is two times the number of comparison scores. The percentage shows how strong the board was.
IMPs measure the size of a score difference. The calculator compares your North-South score with a datum score. It then applies the standard IMP scale. A large vulnerable swing may matter more than several small part scores.
Practical Scoring Notes
Enter scores from the North-South view when using the comparison box. If East-West did well, their result should normally appear as a negative North-South score. Honors are included only as an optional field, because most duplicate events ignore honors. Tournament conditions should always control final reporting.
Use the details panel to audit every step. It shows tricks required, overtricks, penalties, vulnerability, and comparison values. This helps directors, students, and players verify board records quickly before submitting the official board traveler.