How do I find the total cost of a swap before I approve it

05 September 2026

You find the total cost by looking at the final confirmation screen, not the preview screen. The number shown there - the amount you will actually receive, minus all fees - is the only number that matters.

The preview screen shows an estimate. That estimate can change before you approve. Network conditions shift. Exchange rates move. The quoted rate on the preview is a snapshot, not a promise. The confirmation screen shows the binding quote, good for a short window. That is where you see the real total cost.

Here is what you are looking for on that confirmation screen. Three things are subtracted from the amount you send before you get the other token back.

First, the spread. The exchange does not charge a flat fee in most cases. It makes money on the difference between the buy and sell price of the token pair. That difference is built into the rate you see. If you check the market rate on a public order book, the swap rate will be slightly worse. That gap is the spread. It is the exchange's revenue. You cannot see it as a separate line item, but you can infer it by comparing the swap rate to a reference rate from an independent price aggregator.

Second, the network fee. Every transaction on a blockchain requires a fee paid to miners or validators. That fee is separate from the exchange's spread. It pays for the computation and storage your swap uses on the network. The confirmation screen shows it as a network fee or gas fee. It varies with congestion. On Ethereum, it can be several dollars. On Solana, it is often fractions of a cent. The exchange does not control this fee. It passes it through to you.

Third, any additional service fee the exchange charges. Some exchanges add a small fixed percentage on top of the spread. This is less common now, but it exists. It will appear as a separate line item on the confirmation screen, usually labeled "fee" or "service fee."

The total cost is the sum of these three. The amount you receive is the amount you send minus that total. You see that final number on the confirmation screen before you approve the transaction in your wallet.

Do not confuse the preview screen with the confirmation screen. The preview screen is a guide. The confirmation screen is the contract. If the numbers change between them, the confirmation screen is the one you should trust. The difference between quoted and received is a real phenomenon. It happens because the preview quote is based on stale data. The confirmation quote is based on current data. That is why you should always read the confirmation screen carefully.

If you want to understand the full breakdown of where every fraction of a token goes, read the hub page: "What a crypto swap actually costs." That page explains the mechanics in more detail. This page is only about the practical step of finding the number before you approve.

One more thing. The confirmation screen will show a time limit. It might be 30 seconds or two minutes. If you do not approve within that window, the quote expires. You will have to start over. That is normal. Network conditions change. The exchange cannot guarantee a rate indefinitely.

So the process is simple. Look at the preview. Check the market rate on a separate site if you want to estimate the spread. Look at the confirmation screen. Read the number you will receive. Read the network fee. Read any service fee. Approve only if that number matches what you expect. If it does not, cancel and try again.

That is how you find the total cost before you approve it.

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