Free Online Stock Profit Calculator

1. Enter the buy price, sell price and number of shares.
2. Add commission if your broker charges one.
3. Toggle Short selling if this was a short trade.
4. Optionally enter a holding period in days for an annualised return.
5. Review dollar profit, return percentage and net-after-commission profit.

Stock return on a single trade is the percentage change between buy and sell price: (Sell − Buy) / Buy × 100. Multiply by share count for dollar profit, then subtract commissions for net profit. For holding periods other than exactly one year, annualised return scales the result to a one-year equivalent using (1 + return)^(365 / days) − 1, which puts a 3-month trade and a 5-year hold on the same footing.

Active traders log realised trades to track which positions outperformed their hold time. Long-term investors use the annualised view to compare a stock against an index benchmark. The tool accepts buy price, sell price, share count and an optional commission, returning dollar profit, return percentage, net profit after commission and — when a holding period in days is supplied — annualised return. The short-sell toggle flips the math: profit comes from a falling price, so the formula becomes (Buy − Sell) × Shares − Commissions.

Results are pre-tax. Short-term gains in the US are taxed at ordinary income rates; long-term gains get preferential rates. Tax rules change — general information only, consult a qualified tax professional before acting on these numbers.