Glossary › Bid-ask spread
Checked September 25, 2026 · 4 sources · plain-English definition, not financial advice
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%.
The CFTC glossary defines the bid-ask spread as the difference between the bid price and the ask or offer price. On Kalshi you find it from one side of the book: Kalshi's API documentation takes the best Yes bid, derives the best Yes ask as $1.00 minus the best No bid, and subtracts one from the other.
Kalshi's example: best Yes bid 42¢, best No bid 56¢, so the Yes ask is 44¢ and the spread is 2¢. If you buy 100 Yes at 44¢ and immediately sell at 42¢, you lose $2.00 before any fees. The same 2¢ is a much bigger share of a 10¢ contract than of a 90¢ one.
Market makers earn the spread: Kalshi's help center says they make money by collecting the difference between the bid and ask. Kalshi's member agreement adds that market makers may have to keep a maximum spread only at specific times, so spreads can be wider outside them. What to check: the spread relative to the price, and whether a limit order inside the spread could fill instead.
Live Kalshi order book example · Kalshi slippage calculator
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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