Stock Profit Calculator.
The number after costs.
Shares, buy price, sell price. You get the profit, the percentage return, the annualised return and the price at which the trade actually breaks even — with both commissions in the maths. If you bought in more than one lot, get your blended average from the average down calculator first.
Stock Profit Calculator
Profit, return and break-even — commissions included
The Trade
Ready to calculate
Enter the shares and the two prices — fees and holding period are optional
How profit and return are calculated
Four formulas, and the denominator everyone gets wrong
- Gross profit = (sell price − buy price) × shares
- Net profit = gross profit − buy commission − sell commission
- Return % = net profit ÷ total cost × 100
- Break-even price = (total cost + sell commission) ÷ shares
The denominator in the third line is where results get quietly overstated. Return is measured against the capital you committed, including the commission you paid to get in — not against the proceeds you received. Dividing by proceeds makes every winning trade look worse and every losing one look better, which is a strange combination of errors to carry around.
The buy price also deserves a second look. If you built the position in several purchases, the figure that belongs in this calculator is your blended average across all of them. The average down calculator produces that number, and using it here is the difference between measuring your actual result and measuring your first guess.
A worked example, gross and net
150 shares, held six months
You buy 150 shares at $42.50 and sell at $55.00. Your broker charges $10 on each leg, and you held for 180 days.
- Total cost = 150 × $42.50 + $10 = $6,385
- Total proceeds = 150 × $55.00 = $8,250
- Gross profit = 150 × ($55.00 − $42.50) = $1,875
- Net profit = $8,250 − $6,385 − $10 = $1,855
- Return = $1,855 ÷ $6,385 = 29.05%
- Annualised = (1.2905)^(365/180) − 1 ≈ 67.7%
- Break-even price = ($6,385 + $10) ÷ 150 = $42.63
On a position this size the $20 of commission barely registers — it costs 13 cents a share and takes the return from 29.4% to 29.05%. Hold that thought for the next section, because the same $20 behaves completely differently on a smaller trade.
Break-even, and why fees decide small trades
A flat fee does not shrink with your order
Your break-even price is not your entry price. It is your entry price plus whatever the round trip costs, spread across however many shares you own. Since a flat commission stays flat while the position gets smaller, the per-share burden climbs fast.
| Position | Round trip $20 | Gain needed to break even |
|---|---|---|
| 500 shares @ $40 = $20,000 | $0.04 / share | 0.1% |
| 150 shares @ $40 = $6,000 | $0.13 / share | 0.33% |
| 30 shares @ $40 = $1,200 | $0.67 / share | 1.67% |
| 10 shares @ $40 = $400 | $2.00 / share | 5.0% |
A ten-share position at a commission broker needs a 5% gain just to reach zero. That is the real argument against averaging down in many small tranches when you pay per order: each addition carries its own fee, and a plan that looked sensible on paper spends a meaningful share of the capital on the privilege of executing it. Model it before you commit with the average down calculator, which takes the commission as an input for exactly this reason.
Annualised return
The only fair way to compare trades of different lengths
A raw percentage return says nothing about how long the money was tied up. Annualising expresses it as the rate that would compound to the same result over a year, which puts a three-week trade and a three-year hold on the same axis.
Annualised = (1 + Return)^(365 ÷ Days Held) − 1A 12% gain in three months annualises to roughly 57%. The same 12% over three years annualises to under 4% — below what a savings account might have paid for none of the risk. The dollar profit is identical; the quality of the result is not remotely.
One caution: annualising a very short holding period is arithmetic, not a forecast. Projecting a two-week result across a year assumes you could repeat it twenty-six times, which nobody can. Use it to rank trades against each other, not to set expectations. For multi-year holdings the CAGR calculator is the better tool.
Three mistakes that flatter a result
All of them make a trade look better than it was
Dividing by the proceeds instead of the cost
Selling at $50 what you bought at $40 is a 25% return, not 20%. Using the exit price as the denominator understates every gain and is the most common arithmetic slip in this calculation.
Using the first buy price on an averaged position
If you added shares at a lower price, your basis moved. Measuring against your original entry tells you about a position you no longer hold.
Quoting the gross number and spending the net one
Commission on both legs, the spread you cross on the way out, and tax on the gain all sit between the headline and your account. On a short-term US holding, tax alone can take a third.
Partial sales and paper profit
A gain you have not sold is a forecast, not a result
This calculator works equally well on a trade you have closed and one you are modelling, but the two answers mean very different things. A realised profit is money in the account. An unrealised one is the price the market happens to be quoting today, and it can be revised at any moment without asking you.
The distinction matters most when you sell part of a position. Enter only the shares you are actually selling — not the whole holding — because the profit and the tax both apply to that slice alone. Sell 60 of 200 shares and the calculation covers those 60; the remaining 140 carry on with the same cost basis, unchanged by the sale.
One wrinkle that surprises people at tax time: which shares you are treated as having sold may not be the ones you had in mind. In the US, individual stocks default to first-in first-out, so a partial sale draws from your oldest and often most expensive lots unless you identify specific ones at the time of sale. That can turn a gain measured against your blended average into a loss on paper, or the reverse. The cost basis calculator works through the lot-level version.
Frequently asked questions
How do I calculate profit on a stock?▾
Profit = (sell price - buy price) x number of shares, minus the commission on both legs. Buying 150 shares at $42.50 and selling at $55 gives a gross profit of $1,875; with $10 charged on each side, $1,855 is what you keep before tax. The gross figure is the one people quote and the net figure is the one that arrives.
How do I calculate percentage return on a stock?▾
Return = net profit / total cost x 100, where total cost is what you paid including the buy commission. The denominator is the mistake to avoid: return is measured against the money you put in, not against the proceeds you took out. A stock bought at $40 and sold at $50 returned 25%, not 20%.
What is the break-even price on a trade?▾
The exit price at which the trade nets exactly zero: (total cost + sell commission) / shares. With no fees it is simply your buy price. With fees it sits above your entry, and on a small position that gap can be large - $20 of round-trip commission on 30 shares means the stock has to gain $0.67 before you make a cent.
What is an annualised return and why is it different?▾
Annualised return expresses a gain at the rate it would compound to over a full year, which is the only fair way to compare holdings of different lengths. A 12% gain in three months annualises to about 57%; the same 12% over three years annualises to under 4%. Same profit, very different quality of result.
Should I annualise a return from a very short holding period?▾
Treat it as arithmetic rather than a forecast. Annualising a two-week trade projects a fortnight's luck across a whole year and produces numbers that look extraordinary and mean almost nothing. It is useful for comparing trades against each other and misleading the moment it is read as an expected rate.
Does this calculator include tax?▾
No - it stops at net-of-commission profit, because tax rates depend on your jurisdiction, your income and how long you held. In the US the difference between short-term and long-term treatment is usually a larger effect on your outcome than the price you exited at, so run the result through the capital gains calculator before treating this profit as final.
What buy price should I use if I bought in several lots?▾
Your blended average across every purchase, not the price of the first buy. If you have added to the position at different prices, the average down calculator gives you that number. Using the original entry price on an averaged-down position overstates the loss when you are underwater and understates the gain when you are not.
Why is my profit positive but my return small?▾
Because return is scaled to what you deployed. A $500 profit on $50,000 is a 1% return; the same $500 on $2,000 is 25%. A large-sounding profit on a large position is often a mediocre result, and this is exactly why percentage return, not dollar profit, is the number to compare positions with.
How do fees affect small trades?▾
Disproportionately, because a flat commission does not shrink with your order. A $10 round trip on a $500 position is 4% of your capital that the stock has to make up before you are level; the same $10 on a $10,000 position is 0.2%. This is the strongest argument against averaging down in many small tranches at a broker that charges per order.
Can I use this for a loss as well as a profit?▾
Yes. Enter a sell price below your buy price and the result shows the net loss and the negative return, with the fees added to the damage rather than subtracted from a gain. It is worth doing before you sell, not after - seeing the real number including costs sometimes changes the decision.
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Disclaimer: This calculator is for educational purposes only and is not financial or tax advice. Results are net of the commissions you enter but before any tax. Consult a qualified adviser before making investment decisions.