Calculate the complete cost of both trading legs
For a total buying budget A, buy price B and buy fee rate b, the modeled BTC quantity is A ÷ [B × (1 + b)]. Selling that quantity q at price S with sell fee rate s returns q × S × (1 − s). Estimated profit is those sale proceeds minus the original budget and any additional fixed costs.
Percentage fees become decimals in the formula: 0.10% is 0.001. The model treats buying costs as part of the entered budget and charges fees in the quote currency. If an exchange deducts fees from the BTC received, convert that deduction consistently before comparing the resulting sellable quantity.
Use executable prices and matching assets
Compare the same underlying asset and quote currency. BTC/USDT and BTC/USD introduce a currency conversion assumption; wrapped Bitcoin and native Bitcoin can introduce a different asset risk. Use the ask price when buying and the bid price when selling, then account for the order size.
A quoted top-of-book price may only cover a small quantity. For larger trades, use a volume-weighted execution price from the order book. A positive result based on a last-traded price can disappear before either order fills.
Separate an inventory trade from a transfer trade
Selling immediately on the more expensive venue normally requires BTC inventory already available there. Buying first and transferring afterward leaves the sale price uncertain while the transfer settles. A withdrawal fee belongs in your cost estimate, but it does not represent the delay.
Also consider the cost of restoring balances after the trade. This calculator does not model withdrawal suspensions, settlement failures, counterparty exposure or simultaneous execution. A small positive result should be treated as a cost-sensitive scenario that needs executable prices and available balances.
Questions about this tool
Why does the calculator show a loss when the selling price is higher?
The difference between prices must cover the buy fee, sell fee and fixed costs. Those costs can exceed the gross spread, particularly for small trades or routes with expensive withdrawals.
Does the calculator find or execute Bitcoin arbitrage trades?
No. It evaluates prices, quantities and costs you enter. It does not check balances, place orders, reserve liquidity or establish that a transfer route is currently available.