Calculate cost basis per share from total investment and number of shares, or find the missing value when two of the three are known.

Cost Basis Per Share Calculator

Enter any 2 values to calculate the missing variable

Cost Basis Per Share Formula

The following equation is used to calculate the Cost Basis Per Share.

CBPS = TC / S
  • Where CBPS is the cost basis per share ($/share)
  • TC is the total cost (including fees, commissions, etc.) ($)
  • S is the total number of shares

To calculate the cost basis per share, add together all costs associated with purchasing the shares (including fees or commissions), then divide that total by the number of shares.

What is Cost Basis Per Share?

Definition:

Cost basis per share refers to the average amount paid per individual share, taking into account the overall purchase price, fees, and other related costs. This figure is important for accurately calculating capital gains or losses when shares are sold.

How to Calculate Cost Basis Per Share?

Example Problem:

The following example outlines the steps and information needed to calculate the Cost Basis Per Share.

First, determine the number of shares purchased. In this example, 200 shares were bought.

Next, determine the total cost of these shares. Suppose the stock was purchased at $25 per share, and a $10 commission was charged, for a total cost of $5,010.

Finally, calculate the cost basis per share using the formula above:

CBPS = TC / S

CBPS = $5,010 / 200

CBPS = $25.05 / share

FAQ

Why is calculating cost basis per share important?

Knowing your cost basis per share is critical for accurately determining your capital gains or losses when you sell. It ensures you pay the correct amount of taxes on profits and can also help assess the performance of your investment over time.

How do stock splits or dividend reinvestments affect my cost basis?

When a stock splits, the number of shares increases (or decreases, in the case of a reverse split), and the price per share is adjusted accordingly, which affects your overall cost basis distribution. Similarly, dividend reinvestments acquire additional shares, which need to be included to correctly reflect the updated cost basis per share.

Do I need to include fees and commissions in the cost basis?

Yes. Including all fees and commissions associated with purchasing (and in some cases, selling) shares will provide an accurate total cost figure, ensuring your cost basis correctly reflects your total expenditure on the investment.