A bid-ask spread is the difference between the best bid, the highest price buyers are currently willing to pay, and the best ask, the lowest price sellers are willing to accept. In crypto markets, this spread is visible on order book exchanges and represents the most immediate “gap” a trader must cross to buy or sell instantly.
How the bid and ask work in crypto trading
On an exchange, the order book lists buy orders (bids) and sell orders (asks) at various prices. If you place a market buy, you typically pay the current ask; if you place a market sell, you typically receive the current bid. The spread exists because buyers and sellers value immediacy differently and because market makers, firms or traders that continuously quote both sides, often set bids slightly below asks to manage risk and earn compensation for providing liquidity.
A practical example is a token that shows a best bid of 1.00 and a best ask of 1.01. The bid-ask spread is 0.01. A trader who buys at 1.01 and immediately sells at 1.00 would realize a loss roughly equal to the spread, before any fees, illustrating why spreads are a direct part of trading friction.
What affects spreads and why they change
Spreads tend to be tighter in highly liquid markets with many active participants, deep order books, and strong competition among market makers. They often widen during periods of volatility, low trading activity, or around news events, when quoting both sides becomes riskier. Smaller or newly listed tokens may also have wider spreads because fewer participants are willing to provide liquidity at stable prices.
Understanding the bid-ask spread matters because it influences execution quality, effective trading costs, and the reliability of prices across exchanges, making it a core concept for navigating crypto markets efficiently.