Spread
The spread is the gap between the best ask and the best bid in the order book. It is a cost you pay every time you cross it with a market order.
On a busy instrument the spread is often one tick: Tesla’s perpetual on Binance showed a best bid of 382.84 and a best ask of 382.85 on 10 October 2026, a spread of 0.01. On a thin book it can be many ticks wide.
Learn more: what a spread is and bid and ask explained.