What this calculates
The gap between the headline profit on a trade and the money that actually reaches your account is made of commissions and tax. This tool works out both: it takes your share count, buy price and sell price, adds the fees on each side, applies a capital gains rate to the profit, and returns the net figure along with the sell price you needed just to break even.
How the numbers are built
cost = (shares × buy price) + buy commissionproceeds = (shares × sell price) − sell commissionnet profit = proceeds − cost − tax on the gainTax is applied only when the trade is profitable — a loss is left untaxed here, since how losses offset other gains depends entirely on your jurisdiction and the rest of your portfolio.
Worked example
| Amount | |
|---|---|
| 100 shares bought at $45.00 | $4,500.00 |
| Buy commission | $5.00 |
| Total cost | $4,505.00 |
| 100 shares sold at $62.00 | $6,200.00 |
| Sell commission | $5.00 |
| Net proceeds | $6,195.00 |
| Gross profit | $1,690.00 |
| Capital gains tax at 15% | $253.50 |
| Net profit | $1,436.50 |
| Return on cost | 31.89% |
The raw price move was 37.8%. After $10 of commissions and tax, what you keep is 31.9% — the difference is worth knowing before a trade, not after.
Break-even is higher than your buy price
Break-even is the sell price where proceeds exactly cover what you spent, including both commissions. In the example above it is $45.10, not $45.00. On small positions this matters much more than people expect: buying $200 of stock through a broker charging $5 each way means the price has to rise 5% before you are level.
- Commission-free brokers remove most of this, but not spreads — the price you buy at is the ask, the price you sell at is the bid.
- Percentage-based fees scale with the trade, so break-even stays a constant percentage above the buy price.
- Stamp duty, transaction levies and FX conversion on foreign shares all belong in the commission fields.
On the tax rate to enter
- Many countries tax gains on assets held beyond a threshold at a lower long-term rate — enter whichever applies to this holding period.
- Some jurisdictions have an annual tax-free allowance, so your effective rate on a small gain may be zero.
- Gains inside a retirement or tax-sheltered account are usually untaxed at sale — leave the field blank.
- Dividends received while holding are taxed separately and are not part of this calculation.
Frequently asked questions
Why is my return on cost lower than the price change?
How do I model a loss?
Can I use it for a short sale?
What about partial sales?
Does it handle currencies?
Is my trade data stored?
Note
This is an arithmetic tool, not tax or investment advice. Capital gains rules vary widely by country — check your own before relying on the tax figure.