Stock Profit Calculator

When you buy and later sell a stock, your profit isn't simply the difference in share price — it's that difference across all your shares, minus the costs of trading. A stock profit calculator brings those pieces together so you see the real result rather than a rough mental estimate.

The calculation starts with your cost basis: the price you paid per share multiplied by the number of shares, plus any buying commission. Your proceeds are the selling price times the shares, minus any selling fee. The difference between proceeds and cost is your profit or loss. Expressed as a percentage of what you put in, that's your return on investment (ROI) — the figure that lets you compare this trade against others or against a benchmark like an index fund. Buying 100 shares at $50 ($5,000) and selling at $75 ($7,500), with $10 in total fees, nets a $2,490 profit and roughly a 49.7% return.

Fees matter more than many traders realise, especially on smaller positions or frequent trading, where commissions and spreads can erode a meaningful slice of the gain. That's part of why low-cost brokers and buy-and-hold strategies have become popular: every dollar of fees is a dollar off your profit.

Two things this calculator deliberately keeps simple are worth noting. First, the figures are before tax. In a taxable account, a profit may be subject to capital gains tax, and the rate often depends on how long you held the shares — many countries tax long-term holdings more favourably than short-term trades. Second, it measures a single round-trip trade rather than an annualised return; a 50% gain over five years is very different from a 50% gain over five months, so consider the holding period when judging performance. Used as intended, it's a fast, honest scorecard for any individual stock trade.