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What is the order book on Kalshi?

Checked September 25, 2026 · 4 sources · plain-English definition, not financial advice

How it works on Kalshi

Kalshi's help center says the order book displays all the resting orders in a market with their quantities and prices, and can be toggled between bids (the most a buyer will pay) and asks (the least a seller will accept). Under rule 5.9 of Kalshi's rulebook, orders match by price first and then by time: better prices fill first, and at the same price the oldest order fills first.

Kalshi's API returns only bids for both sides, because a Yes bid at a price is the same as a No ask at $1 minus that price. Kalshi's own example: the best Yes bid is 42¢ and the best No bid is 56¢, so the best Yes ask is $1.00 minus 56¢, or 44¢, and the spread is 2¢.

What to check: depth, not just the top price. Kalshi's rulebook says members can see the best bid and offer, open interest, trade volume and the depth of the book up to the fifth price level. A large order works down those levels, so its average price is worse than the top quote.

Related terms

• Bid and ask: The bid is the highest price a buyer offers and the ask the lowest price a seller accepts; on Kalshi a No bid at 30¢ is a Yes ask at 70¢.
• Bid-ask spread: The gap between the best bid and best ask in a Kalshi market; crossing it costs money, so a 2¢ spread on a 44¢ contract is about 4.5%.
• Resting order: A limit order, or its unfilled part, waiting in a Kalshi order book; it fills only when someone trades against it and can be canceled at no cost.
• Liquidity: How easily you can buy or sell a Kalshi contract near the quoted price; deep order books and tight spreads mean good liquidity.
• Limit order: An order to buy or sell at your price or better; on Kalshi any part that does not match right away rests on the order book until filled or canceled.

See also

Live Kalshi order book example · Order book guide: bid, ask and depth · Kalshi slippage calculator

Sources

1. The Orderbook, Kalshi Help Center, March 10, 2026
2. Orderbook Responses, Kalshi API documentation, accessed September 25, 2026
3. KalshiEX LLC Rulebook, version 1.29, Kalshi, accessed September 25, 2026
4. CFTC glossary: Order Book, U.S. Commodity Futures Trading Commission, accessed September 25, 2026

Checked September 25, 2026. Kalshi changes fees, rules, funding options and limits; the market's rules, the order ticket and Kalshi's help center are the final word.

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