How do you calculate stock cost basis
14 Jan 2020 It is used to calculate the capital gain or loss on an investment after it's been sold, for tax purposes. key takeaways. Calculating the cost basis of� 16 Jan 2020 Understanding how to calculate cost basis is critical for tracking the gains stocks, bonds, and options, calculating cost basis accurately for tax� Consider the earliest shares as the one's sold first. Multiply the purchase price from this sale by the number of shares sold to calculate this portion of the cost basis.