I've noticed that many beginners in crypto completely overlook one factor that really affects their profit. It's about the spreads between the buy and sell prices — that very gap that exists in the order book between the best bid and the best ask.

Look: if you open the order book, you'll see that the highest price someone is willing to buy an asset at and the lowest price someone is willing to sell don't match. There's always a difference between them — that's the bid-ask spread. For example, from the order book: a bid of $22,346 and an ask of $22,347 — a one-dollar difference. It sounds trivial, but it's not.

This bid-ask gap mainly depends on market liquidity. On large exchanges with high volume, the spread is narrow — there are many participants competing, and prices tend to converge. On illiquid markets, the spread widens, especially when volatility is high or uncertainty is elevated. When the market panics, liquidity evaporates, and the spread can suddenly increase.

How do you calculate it? Simply: subtract the best bid from the best ask. For example, with Ethereum: if the ask is $1570 and the bid is $1570.50, then the spread is 50 cents. Simple and clear.

Now, the most important part — why does this matter for your trading? Every time you enter a position, you buy at a higher price (ask), and when you exit — you sell at a lower (bid). This difference eats into your profit. It may seem like pocket change, but with frequent trading, it adds up to serious money.

A practical example: you're trading coin ABC, fair price is $0.35, and the spread is $0.02. You buy at $0.36 (best ask), and the best bid for selling is $0.34 (best bid). To break even, the price needs to rise by about 5%. And that's just on one trade. If you trade actively, bid-ask spreads gradually eat more and more of your capital. That's why choosing an exchange with good liquidity isn't just about convenience — it directly impacts your income.