Bitcoin purchase costs: trading, FX and withdrawals

Write down the whole cost chain

Use five lines: funding, currency conversion, trading commission, execution difference and withdrawal. Record each fee in its original currency and whether it has already been included in the quote. Convert currencies with the actual rate used for your transaction, not an unrelated reference rate.

For a fixed budget, subtract charges taken before the trade, determine how much BTC the actual execution would buy and subtract a withdrawal fee denominated in BTC where applicable. A percentage fee and a fixed network or withdrawal charge affect small purchases differently.

When two offers use different products or execution methods, return to the platform total-cost checklist before treating their quoted rates as comparable.

Worked SEK example: inputs, formula and unknown costs

This is a reproducible calculation from public documents, not an executed trade or a live quote. Sources reviewed on 28 October 2026: the ECB reference for 27 October is 1 EUR = 11.0795 SEK; Kraken Pro's standard Tier 1 spot taker rate is 0.80%; the selected published EUR SEPA deposit routes list a 0 EUR deposit charge, subject to route and account eligibility. The ECB reference is not a bank conversion offer.

Model assumptions: a total budget of 10000 SEK, a 20 SEK bank transfer charge, a 1.00% bank conversion markup over the ECB reference, and an illustrative execution price of 75000 EUR per BTC. The trading fee is paid in EUR from the same budget. The bank charge, markup and Bitcoin price are chosen assumptions, not observed customer quotes.

Let R = 11.0795, A = 20, m = 0.01, f = 0.008 and H = 75000. The applied conversion rate is E = R × (1 + m) = 11.190295 SEK/EUR. Credited cash C = (10000 − A) / E = 891.84422752 EUR. With the fee inside the cash budget, traded principal P = C / (1 + f) = 884.76609873 EUR and trading fee F = C − P = 7.07812879 EUR. Bitcoin before withdrawal is P / H = 0.0117968813164 BTC.

Using unrounded intermediate values, the model allocates 20.00 SEK to the bank charge, 98.81 SEK to the assumed conversion markup C × (E − R), and 78.42 SEK to the trading fee valued at the ECB reference F × R: 197.23 SEK for these components. For display, cash is 891.84 EUR, principal 884.77 EUR, fee 7.08 EUR and Bitcoin 0.01179688 BTC. Round cash to 2 decimals and Bitcoin to 8 using half-up rounding only at the end; displayed rounded subtotals can differ slightly.

This is not the full cost of a real delivery to a wallet. The actual bank quote, execution price, bid-ask spread or slippage and Bitcoin withdrawal charge remain unverified. If W is the actual quoted withdrawal fee in BTC, the amount received is P / H − W, subject to the provider's minimums and network conditions. Do not set W to 0 when it is unknown. Replace the assumptions with the same account's final previews and timestamps; do not count a charge again if it is already included in a quote.

Calculate a commission without calling it the total cost

At a published rate of 0.80%, a EUR 1,000 trade has EUR 8 of trading commission; at 0.40%, the corresponding commission is EUR 4. These are arithmetic examples using Kraken Pro's observed Tier 1 schedule, assuming the full EUR 1,000 is the fee basis. They exclude funding, FX, spread, slippage and withdrawal costs.

The EUR 4 difference does not mean that every limit order saves EUR 4. An immediately executable limit order can take liquidity and incur a taker fee. An order that rests on the book may not fill, and a fee tier can change with account qualification. Match the calculation to the product and account you will actually use.

Separate a provider spread from market execution

A simple buy quote can contain a provider-added spread. An order-book product can remove that particular markup while still exposing you to the market bid-ask spread and slippage. The last traded price is not a promise that your whole order can execute at that level.

Compare quotes taken close together and for the same amount. Otherwise, market movement can be mistaken for a difference in fees. Retain both the fee and the asset quantity shown in the preview so that the comparison can be checked later.

Use the actual withdrawal preview

An exchange's withdrawal fee is not necessarily identical to the fee the Bitcoin network charges for the exchange's own transaction. Exchanges can batch withdrawals or set their own charge. Inspect the selected network, minimum and final amount shown before confirmation.

Do not assume a free or cheap transfer on another network delivers native Bitcoin to your chosen address. Wrapped assets and alternative networks create a different product and risk profile. The destination wallet must support the precise asset and network selected.