Bid-Ask Spread Definition

The bid-ask spread is the gap between the highest price buyers are offering (the bid) and the lowest price sellers will accept (the ask). You’ll see it on an order book for any market, including crypto. A tighter gap usually points to a more active market.

How it is calculated

In plain terms, spread = ask price minus bid price. If the ask is higher than the bid, the difference is the spread you pay if you hit the market immediately. 

Where it shows up in practice

On exchanges, the order book stacks bids from buyers and asks from sellers. The top bid is the most any buyer currently offers, and the top ask is the least any seller will take. The spread sits right between those two top quotes. 

Why traders care

The spread acts like an implicit trading cost. Even if fees look low, buying at the ask and selling at the bid creates a small loss equal to the spread, so frequent traders pay close attention to it. In crypto glossaries, the spread is framed as a signal of both liquidity and transaction cost. 

What makes a spread tight or wide

• Trading volume and liquidity: Heavily traded pairs usually have narrower spreads because there are many orders on both sides. Thin markets tend to have wider spreads. 
• Volatility and market conditions: Sudden price moves or quiet periods can widen spreads as participants adjust or pull orders.
• Asset popularity: Major coins typically show smaller spreads than niche tokens.

A quick example

If the best bid for a token is 2,345 and the best ask is 2,350, the spread is 5. That difference is exactly what you face if you buy at market and then immediately sell at market. 

Spread vs. slippage

• Spread is the built-in gap between the top bid and top ask before you trade.
• Slippage is the difference between the price you expect and the price you actually get after your order fills, which can be affected by liquidity and order size.

‍