Cost Basis Calculator

About this calculator

The cost basis of an investment is the total amount actually paid to acquire it, including the purchase price plus any commission or brokerage fees — not just the raw share price. It's the baseline figure used to calculate capital gains or losses when the investment is eventually sold: profit is the sale proceeds minus the cost basis.

This calculator computes both the total cost basis and the cost basis per share from your share count, purchase price, and fees. It's a routine calculation for investors and tax preparers, since accurately tracking cost basis — especially across multiple purchases of the same stock at different prices and dates — is required for correct capital gains tax reporting and for deciding which shares (or “tax lots”) to sell for the best tax outcome.