Bid and ask
The bid is the best price someone will currently pay for an asset, and the ask is the best price someone will currently sell it for. The gap between them is the spread.
How it works
In the order book buyers post bids and sellers post asks. The bid is always below the ask; otherwise a trade would already have happened. The price on the chart is usually the last trade price, but an instant buy is only possible at the ask.
If you buy with a market order, you pay the ask. If you sell with a market order, you get the bid. That is why a position shows a small loss right after you buy: selling instantly is only possible at the lower price.
Bid and ask show how liquid a market is. For popular pairs they nearly touch; for obscure coins there can be a wide gap. In forex, quotes also come as a bid/ask pair, and the broker earns partly from the difference.
On ETH/USDT the bid is 2,499.50 and the ask 2,500.00. You buy 1 ETH at market and pay 2,500. Sell straight away and you get 2,499.50, losing $0.50 on the spread plus fees. On a thin coin with a $0.98 bid and $1.02 ask, an instant round trip costs about 4%.
The mistake is watching only the last price on the chart and being surprised you paid more. Before trading, look at the bid and ask: when buying, think in terms of the ask; when selling, the bid. On illiquid markets use limit orders rather than market orders so you do not overpay.
Questions and answers
What are bid and ask in simple terms?
The bid is what buyers are willing to pay; the ask is what sellers want. You can buy instantly at the ask and sell instantly at the bid.
Why is the ask always higher than the bid?
If a buyer were willing to pay what a seller asks, the trade would already have happened. The best remaining orders leave a gap, which is the spread.
What price will I get with a market order?
The ask when buying, and if there is not enough size at the best price, part of the order fills at the next, higher prices. That is slippage.
Related terms
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Updated: 2026-10-19