📈 Stock Profit Calculator
Realized profit/loss for one buy–sell round trip, commissions included.
🔒 100% client-side processing
Result
Total cost
Total proceeds
Net P/L
ROI
Break-even sell price
Enter prices manually — this tool does not fetch live quotes. Long positions only; shorting and dividends are not included.
The Stock Profit Calculator works out the result of a single completed buy-then-sell trade. Enter the buy price, sell price, share count, and each leg’s commission, and it returns total cost, total proceeds, net profit or loss, return on investment as a percentage, and the break-even sell price. It models one long round trip, uses plain currency-agnostic numbers, and runs entirely in the browser.
How to Use
- Enter the buy price, the sell price (actual or planned), and the number of shares.
- Enter the buy and sell commission, each as a flat amount or a percentage of that leg’s value. Mixing modes is allowed — for example a flat buy fee and a percentage sell fee.
- Read the breakdown: total cost, total proceeds, net P/L, ROI percentage, and break-even sell price.
- Optionally type a currency symbol such as
$,€, or¥for display. The symbol does not affect the math.
The Formulas Behind the Results
Let B be the buy price, S the sell price, N the share count, and F the fee on a leg.
- Buy value:
B × N - Buy fee: flat amount, or
pct ÷ 100 × (B × N) - Total cost:
(B × N) + buyFee - Sell value:
S × N - Sell fee: flat amount, or
pct ÷ 100 × (S × N) - Total proceeds:
(S × N) − sellFee - Net profit/loss:
proceeds − cost - ROI:
profit ÷ cost × 100 - Break-even, flat sell fee:
(cost + flatSellFee) ÷ N - Break-even, percentage sell fee:
cost ÷ (N × (1 − pctSellFee ÷ 100))
Note that cost already includes the buy fee, which is why the break-even price sits above the buy price even when the sell side is free. ROI is measured against total cost including fees, not against the raw share value, so it is slightly lower than the naive (S − B) ÷ B figure whenever fees are charged.
Worked Examples
A profitable trade with no fees. Buy 10 shares at 100, sell at 120: cost 1,000, proceeds 1,200, net profit 200, ROI 20.00%, break-even 100.00. With no fees, ROI matches the raw price gain exactly.
A losing trade with flat commissions. Buy 100 shares at 50 with a 5 buy fee, sell at 48 with a 5 sell fee: cost 5,005, proceeds 4,795, net profit −210, ROI −4.20%. Break-even is (5,005 + 5) ÷ 100 = 50.10 — the price has to climb back above the purchase price before the trade is even.
A percentage sell fee. Buy 100 shares at 100 with no buy fee, then sell at 110 with a 1% sell fee: proceeds are 11,000 − 110 = 10,890, so net profit is 890 and ROI is 8.90%, lower than the 10% price gain. Break-even is 10,000 ÷ (100 × 0.99) = 101.01.
Flat vs Percentage Commissions
The fee mode matters most on small trades and large ones, in opposite directions. A flat fee is a fixed cash cost, so it hits a 10-share trade far harder proportionally than a 1,000-share trade. A percentage fee scales with the position, so it is lighter on small trades and heavier on large ones. The break-even table shows the difference:
| Sell fee on 100 shares, cost 10,000 | Break-even price |
|---|---|
| No fee | 100.00 |
| Flat 5 | 100.05 |
| 0.5% of sell value | 100.50 |
| 1% of sell value | 101.01 |
Percentage fees move break-even further because the fee itself rises as the price rises, which is why the percentage rows diverge faster than the flat row.
What the Calculator Excludes
The result is a pre-tax, single-trade figure. It does not include capital gains tax, dividend income or withholding, stamp duty, regulatory transaction levies, platform or data fees you did not type in, currency conversion spreads, margin interest, or opportunity cost. It cannot model shorts, options, partial sells, multiple lots at different prices, or corporate actions such as splits. If any of those apply, adjust the inputs or compute the missing pieces separately rather than treating the net profit as your final realized gain.
Common Mistakes When Reading the Result
- Confusing ROI with the price move. If you buy at 100 and sell at 110, the price rose 10%, but ROI is measured against total cost including fees, so it comes out a little lower. The gap widens as commissions grow.
- Entering a percentage fee as a decimal. The percentage field is a percent, not a fraction: enter
1for one percent, not0.01. Entering0.01charges one-hundredth of a percent. - Forgetting the buy-side commission. Cost includes it, and it pushes break-even above your purchase price. A break-even above the buy price is expected whenever fees are non-zero.
- Treating net profit as taxable gain. The figure is pre-tax. Capital gains rules, holding periods, and loss-offsetting are all applied elsewhere.
- Over-trusting the displayed decimals. The internal result is exact and shown rounded to two decimals, so chaining several displayed round trips together can accumulate small differences.
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Frequently Asked Questions
Does the calculator include capital gains tax?
No. It nets out the buy and sell commissions you enter, but it knows nothing about capital gains tax, stamp duty, transaction levies, or currency conversion costs. Those depend on your jurisdiction and holding period. Use the net profit it reports as a pre-tax figure, then apply your own tax treatment.
Why is the break-even price higher than the price I paid?
Because you also have to recover the buy commission, and usually the sell commission. Cost includes the buy fee, so the sell price must cover that fee plus the sell-side fee before profit reaches zero. With buy and sell fees both at zero, break-even equals the buy price exactly.
How does a percentage sell fee change the break-even price?
A flat sell fee is added to cost and then divided by the share count: (cost + flat) ÷ shares. A percentage fee grows with the sell price, so it is solved differently: cost ÷ (shares × (1 − pct ÷ 100)). For a cost of 10,000 on 100 shares with a 1% sell fee, break-even is 10,000 ÷ (100 × 0.99) = 101.01, not 101.00.
Can I model short selling, options, or dividends?
No. The calculator handles one long buy-then-sell round trip. Short positions involve borrow fees, margin interest, and potentially unlimited loss; options have their own pricing and assignment mechanics; dividends add income and tax complexity. All of those are intentionally outside the model.
I bought the same stock several times at different prices. Can I enter multiple lots?
Not directly. Compute your average cost per share first, using total cost divided by total shares, and enter that average as the buy price. Note that averaging ignores how individual lots are treated for tax under first-in-first-out or specific-identification rules, so the tax figure will differ even when the untaxed profit matches.
What happens if the sell price is zero?
A sell price of zero is allowed and models a total loss: proceeds become zero minus the sell fee, so the net result is the negative of the total cost. The buy price and share count, by contrast, must both be greater than zero. A percentage sell fee of 100% or more is rejected because it makes break-even impossible.
Reviewed by the HandyTools Hub team · Last updated