How Does Bridge Bidding Work? The Auction Explained

What the Bidding Rules Cover

The auction is the part of bridge bidding where the four players decide the final contract: how many tricks one side will try to make and in which trump suit (or no-trump). The rules here are not about what a bid means to your partner; they are about which calls are legal and how the auction is conducted. Learn them once and they become second nature.

There are only three kinds of call: a bid (a number plus a denomination, such as 1♥ or 3NT), a pass, and the competitive calls double and redouble. The dealer calls first and the turn rotates clockwise.

The Ranking of Bids

Every bid names a level (1 to 7) and a denomination. The denominations rank from low to high, and within a level a bid must beat the previous one by going up in rank or up in level.

So 1♠ is higher than 1♥, and 2♣ is higher than 1NT. A "level" is the number of tricks above six that you contract to win: a 1-bid promises seven tricks, a 7-bid all thirteen. Because there are five denominations and seven levels, there are 35 possible contracts, mapped out in our bidding chart.

Pass, Double and Redouble

You are never forced to bid: you may pass on any turn, and bid later if the auction comes back to you. The competitive calls add two more options:

A double can only be made over an opponent’s bid, and a redouble only over an opponent’s double. The meaning of a double depends on partnership agreement: for the common conventional uses see takeout doubles and negative doubles.

How the Auction Ends

The auction continues clockwise until a call is followed by three passes in a row. The last bid then becomes the contract, and the side that made it must try to win that many tricks.

If all four players pass on the opening round: four passes with no bid: the hand is "passed out" and thrown in with no score, then the next deal is played.

Insufficient and Illegal Bids

A bid must be higher than the last bid. A call that is not: for example 1♣ over an existing 1♦: is an insufficient bid and is not allowed. In casual play you simply correct it; in duplicate bridge the director is called and a rectification is applied. You also cannot bid out of turn or change a call once it has been accepted.

None of this should intimidate a beginner. At the kitchen table the rules are forgiving: keep the bids climbing, take turns clockwise, and let three passes close the auction.

Reading the Final Contract

Once the auction ends, the contract tells you everything about the goal. The declarer is the player on the winning side who first named the final denomination; their partner becomes the dummy. The player to the left of declarer makes the opening lead, and play begins.

Common Rule Misunderstandings

• Thinking a pass ends your bidding. A pass only ends your current turn: you can bid again when the auction returns to you.
• Believing no-trump ranks below the suits. No-trump is the highest denomination, so 1NT outranks 1♠.
• Doubling your own side. You can only double a bid made by an opponent, never partner.
• Forgetting three passes are needed. One pass does not end the auction after a bid: it takes three consecutive passes.

What Are the Core Rules Every Bridge Bidder Must Know?

Bridge bidding is a conversation between partners using a shared language of bids. Each bid carries a specific meaning about your hand's strength and shape. The core rules govern when to open, how to respond, and when the auction has established enough information to place the final contract. Understanding these rules is not optional: without them, you are guessing, and your partner cannot bid accurately because they do not know what your bids mean.

The five most important rules: open with 12 or more HCP (or a hand meeting the Rule of 20); respond to partner's opening with 6 or more HCP; raise partner's major with three-card support and the right strength; bid your own suit at the one-level to show four or more cards; and always show the shape of your hand before showing its strength when those are in conflict.

These rules apply across all versions of Standard American. They hold whether you play two-over-one game force or standard responses. Our full opening bids guide covers the full opening framework in detail.

How Forcing, Non-Forcing, and Game-Forcing Bids Work

Understanding forcing bids is essential to preventing misunderstandings. A forcing bid requires partner to bid again. A non-forcing bid gives partner the option to pass. A game-forcing bid commits both partners to bidding until a game contract is reached.

The most common forcing situations: a new suit by responder at the one-level after opener's bid is one-round forcing; a jump shift by responder (bidding a new suit at a level higher than necessary) is game-forcing; any bid of a new suit by opener after opening is forcing for one round unless partner passed originally. Knowing which bids are forcing and which are not is more important than knowing which specific conventions to play.

The most common confusion: players who pass a forcing bid because they have a weak hand. Passing a forcing bid is one of the worst errors in bridge bidding because it leaves partner in an impossible contract with no information about what you hold. If partner makes a forcing bid, you must bid, even with the weakest possible hand consistent with your previous bidding.

Standard Bidding Rules at a Glance

For conventions that work within these rules, see our guides to Stayman and Blackwood.

What Are the Rules for Bidding in Competition?

When the opponents enter the bidding after your opening, the rules shift. Your bids now carry a dual purpose: showing your hand to partner and competing for the contract. The key rule in competition: a bid in a new suit is no longer automatically forcing if the opponents have bid. After interference, responder's new suit is typically non-forcing unless a specific conventional agreement makes it forcing.

After an overcall by the opponents, a double by your partner is a negative double (showing the unbid suits and at least 6 HCP), not a penalty double. This is the most common misunderstanding for players new to competitive bidding. If your partner doubles an overcall at the one or two level, they are asking you to bid, not saying they want to penalize the opponents.

The cuebid of the opponents' suit (bidding the suit they bid) is a strong, forcing bid showing support for partner's suit and game-invitational or better values. It replaces the jump raise in competition. For example: if you open 1-spade and the opponent overcalls 2-hearts, your partner bidding 3-hearts is a cuebid showing spade support and 10+ HCP. Our takeout doubles guide and negative doubles guide cover competitive bidding in detail.

When Should You Pass Instead of Bidding in Bridge?

Passing is one of the most underused bids in bridge. Many players feel that passing shows weakness or gives up the auction unnecessarily. In fact, passing is often the correct action, and the players who pass well win more than those who always try to find a bid.

Pass when you do not have the values to bid, when your hand does not fit any of the available bids accurately, or when the opponents have already found their best contract and any bid risks getting your side into a worse position. The saying in bridge is: "When in doubt, pass." The corollary: "When not in doubt, also consider passing."

The specific situations where passing is clearly right: responding to partner's opening with fewer than 6 HCP; choosing not to overcall without a good 5-card suit and 9+ HCP; and leaving the opponents in a contract you believe they will not make rather than pushing them to a better one. Our common bidding mistakes guide covers the specific situations where bidding when you should pass costs the most points.