Calculate each purchase before combining the rows
For a row with quote amount A, purchase price P and fee rate f, the BTC acquired is A × (1 − f) ÷ P. The quote amount includes the fee budget in this model. Sum the acquired BTC across all rows to obtain the total base quantity.
Sum the full quote amounts to obtain the total purchase outlay. The effective average purchase price is total outlay divided by total BTC acquired. Because fees reduce the quantity purchased, this effective average will be higher than the comparable average calculated with the same prices and zero fees.
Why averaging the displayed prices gives the wrong answer
A simple average assigns equal weight to each purchase price. Your holdings depend instead on how much quote currency was spent and how much BTC each payment acquired. Even equal quote payments buy unequal BTC quantities when prices differ.
This means a price average can differ from the cost of the actual position without either individual purchase record being wrong. The difference becomes more noticeable when purchases vary in size or when prices are far apart. Combining the quantities and outlays first keeps the calculation tied to what was acquired.
Keep the fee convention and transaction scope consistent
Some platforms charge fees on top of the entered purchase amount, while others deduct fees from the budget or from the BTC delivered. The row model here deducts a percentage from the quote budget. Convert an actual transaction to that convention before mixing it with other rows.
The calculator combines purchases only. Sales, withdrawals, transfers, rewards and separately paid network fees do not automatically update the result. Its average cost is an analytical summary, not a selection of tax lots or a portfolio-performance measure. Use consistent quote currencies and actual fill prices across the rows.
Questions about this tool
Does the amount in each row include the trading fee?
Yes. The model deducts the row's percentage fee from the quote amount and uses the remainder to buy BTC. If your exchange charged the fee on top, convert the transaction into a fee-inclusive budget before entering it.
Can I include a partial sale in the DCA rows?
No. These rows represent purchases, not disposal accounting. A sale changes the remaining position and can require a chosen cost-basis method. Adding a negative purchase would not provide a reliable reconstruction.