Transparent methodology
How the real-cost model works
The calculator is designed to expose assumptions, not hide uncertainty behind a single fee number.
Core formula
Estimated BTC received = (purchase amount − funding cost − trading cost − spread cost − withdrawal cost) ÷ BTC price.
Funding, trading, and spread costs are percentages of the relevant fiat amount. The withdrawal input is denominated in BTC and converted using the editable BTC price.
Exchange fields
Base maker and taker fees come from the site exchange dataset. Card and P2P percentages are parsed only when the editorial record contains a numeric estimate. If no usable number exists, the calculator uses the fallback funding fee entered by the user.
Spread
Spread is not the same as an advertised trading fee. It represents the difference between a reference market price and the price actually offered or executed. The default is an educational assumption and should be replaced with the quote visible at checkout.
Withdrawal cost
Exchange withdrawal charges are dynamic and can differ from the miner fee shown on the Bitcoin network. The calculator therefore keeps the BTC withdrawal amount editable instead of presenting a static platform quote as live.
Not included
The model does not include taxes, card foreign-exchange charges, bank fees, price movement while an order is pending, large-order slippage, VIP fee tiers, promotions, rebates, or every regional restriction.
How to use the result
Treat the result as a pre-purchase checklist. Immediately before buying, copy the exchange’s exact funding fee, quoted BTC price, trading fee, and withdrawal charge into the calculator.