Determine the par value of stock sold. Suppose the par value of stock is $60 per share.
Determine how many shares of stock the company has issued. Suppose the company issued 1,000,000 shares of stock.
Determine at which price the stock was sold to investors. Suppose the selling price for shares of stock is $80.
Calculate the additional paid-in capital. Subtract the par value of the shares from the capital received from the sale of shares to investors. In our example, the calculation is this: $80 million - $60 million = $20 million. The additional paid in capital in $20 million.