Why does the final Bitcoin amount in my wallet differ from the swap screen

05 September 2026

The final Bitcoin amount in your wallet differs from the swap screen because the quoted figure is an estimate that cannot account for mempool congestion, miner fee fluctuations, or the exchanger's final execution rate. The swap screen shows a snapshot of conditions at that moment; by the time your transaction settles, those conditions have shifted.

Here is why the number changes, broken into the factors at play.

The swap screen shows a preliminary quote, not a guaranteed receipt. When you initiate a swap from, say, a stablecoin into Bitcoin, the platform estimates how much BTC you will receive based on current exchange rates and expected network fees. That estimate includes assumptions: that your deposit arrives quickly, that Bitcoin's mempool does not spike, and that the exchanger's liquidity pool remains stable. None of these assumptions hold perfectly.

Bitcoin transaction fees are not fixed. The swap screen typically includes a fee estimate for moving Bitcoin from the exchanger to your wallet. That fee depends on the byte size of your transaction and the fee rate (satoshis per byte) at the moment the transaction is broadcast. If the mempool grows between the quote and the actual broadcast, the fee may need to be higher to confirm in a reasonable time. The exchanger either absorbs that difference or passes it on, reducing your final amount. Conversely, if the mempool clears, you might receive slightly more - though that is less common.

Exchange rates drift. The swap screen freezes a rate for a few seconds or minutes. Crypto prices move constantly. If Bitcoin's price changes between the quote and the settlement, the exchanger adjusts the rate to reflect the market. This is not a hidden fee; it is the same mechanism as any currency conversion. The longer the swap takes, the larger the potential drift. Bitcoin swaps are slower than trades on faster chains (covered in a sibling page), so drift is a real factor.

Network confirmations matter. The swap screen often quotes the amount after a certain number of confirmations (usually one or two for Bitcoin). If the network is congested, your transaction might confirm later than expected, and the exchanger may apply a penalty or recalculate the rate. Some platforms also require multiple confirmations for large amounts, which extends the window for rate changes.

The exchanger's fee structure is not always transparent. The swap screen may show a "network fee" or "service fee" but omit variables like a spread on the exchange rate. That spread - the difference between the buy and sell price of Bitcoin - is how the exchanger makes money. It is included in the quoted amount, but if the spread widens due to low liquidity or volatility, the final amount shrinks. You can see this by comparing the swap screen's implied rate to a public index price at the same moment.

What you can check. After the swap completes, compare the transaction ID on a Bitcoin block explorer (like mempool.space) with the swap screen's quoted amount. The explorer will show the exact output to your wallet and the fee paid. If the difference is larger than a few percent, look at the mempool conditions at the time of broadcast. Most variation is explained by timing and fees, not malfeasance.

For a deeper understanding of how Bitcoin's design affects swaps, see the hub page "Swapping Bitcoin for other assets." It covers the broader constraints that make Bitcoin different from faster chains - and why your final amount is rarely a perfect match to the preview.

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