Stock Profit Calculator
How to Use This Stock Profit Calculator
This calculator helps you estimate the profit or loss from a stock trade. Enter your buy price per share, number of shares, sell price per share, and any commissions or trading fees you paid when buying and selling. The tool then computes your total cost, total proceeds, net profit or loss, and percentage return on investment (ROI).
It is designed for individual investors and traders who want a quick, clear view of how a trade performed or how a planned trade might turn out before placing an order.
Core Formulas Behind the Calculator
The calculator uses straightforward arithmetic to break your trade into three main components: total cost, total proceeds, and net result. In plain-text form:
- Total cost = (Buy price per share × Number of shares) + Buy commission
- Total proceeds = (Sell price per share × Number of shares) − Sell commission
- Net profit or loss = Total proceeds − Total cost
- ROI (%) = (Net profit or loss ÷ Total cost) × 100
Written in a more compact way:
ROI (%) = (Proceeds − Cost) ÷ Cost × 100
The same idea can be expressed with MathML for clarity:
where P is total proceeds and C is total cost. A positive result indicates a gain; a negative result indicates a loss.
Interpreting Your Results
After you enter your trade details and run the calculation, you will typically see:
- Total cost: The full amount of capital you committed to the trade, including your buy-side commission or fees.
- Total proceeds: The cash you received from selling the shares, after subtracting any sell-side commission or fees.
- Net profit or loss: The difference between proceeds and cost. A positive number means you made money; a negative number means you lost money.
- Return on investment (ROI): Your net result expressed as a percentage of the capital you originally put at risk.
These metrics let you quickly answer questions such as:
- How much did this trade actually make or lose after fees?
- Was the return attractive compared with other opportunities?
- How sensitive was the result to commissions or small price changes?
In general, the higher the ROI, the more efficiently you used your capital. However, ROI should always be considered alongside risk, holding period, and your broader portfolio objectives.
Worked Example: From Trade Details to ROI
Consider the following example to see how the calculator’s logic plays out step by step.
Scenario:
- Buy 150 shares at $20.00 per share
- Buy commission: $7.00
- Sell 150 shares at $26.00 per share
- Sell commission: $9.00
1. Compute total cost
Share cost = 150 × 20 = $3,000
Total cost = $3,000 + $7 = $3,007
2. Compute total proceeds
Gross sale value = 150 × 26 = $3,900
Total proceeds = $3,900 − $9 = $3,891
3. Compute net profit
Net profit = $3,891 − $3,007 = $884
4. Compute ROI
ROI (%) = ($884 ÷ $3,007) × 100 ≈ 29.4%
If you enter these same inputs into the calculator, you should see a profit around $884 and an ROI of just under 30%. This illustrates how even modest price differences can produce sizable percentage gains when leverage or concentrated positions are involved. It also shows how commissions slightly reduce your overall return.
Why Commissions and Fees Matter
Commissions and trading fees may seem minor, but they can materially affect your outcome, especially if you:
- Trade frequently or in and out of positions quickly.
- Buy small numbers of shares where fees are a large fraction of your investment.
- Use brokers that charge per-trade or per-share commissions.
By entering buy-side and sell-side commissions separately, the calculator forces you to account for these costs. This can help you identify trades where apparent gains are mostly eaten up by fees. For brokers that advertise “zero-commission” trading, you can leave the commission fields at zero, but remember that other costs (such as bid–ask spreads or regulatory fees) may still reduce real-world profits.
Comparison: With vs. Without Commissions
The table below shows how the same trade can look different when you consider commissions explicitly.
| Scenario | Total Cost | Total Proceeds | Net Profit / Loss | ROI (%) |
|---|---|---|---|---|
| Ignoring commissions | $3,000 | $3,900 | $900 | 30.0% |
| Including $7 buy and $9 sell commission | $3,007 | $3,891 | $884 | ≈ 29.4% |
| Higher-fee broker (e.g., $20 total commissions) | $3,010 | $3,880 | $870 | ≈ 28.9% |
This comparison highlights that even small differences in fees can add up over many trades. Using the calculator consistently can help you choose position sizes and trading frequencies that leave more of your gross gains in your pocket.
Assumptions and Limitations
This stock profit calculator is intentionally simple. It is built to answer the question, “If I buy at this price and sell at that price, with these commissions, what is my profit or loss?” To keep the tool fast and easy to use, it relies on several assumptions:
- Single buy and single sell: The calculator assumes one opening purchase and one closing sale of the same number of shares. It does not natively model multiple entry or exit points, layered orders, or partial fills.
- Simple ROI, not annualized: ROI is calculated as a straightforward percentage of your original cost. It does not adjust for how long you held the position or convert returns into annualized or risk-adjusted metrics.
- Taxes and regulatory fees excluded by default: Income taxes, capital gains taxes, transaction taxes, and small regulatory charges are not automatically included. If you want to approximate them, you can add expected costs to the commission fields.
- No automatic currency conversion: The calculator treats all amounts as if they are in the same currency. If you trade foreign stocks, you will need to convert values to your base currency before entering them.
- No explicit dividend handling: Dividends are not modeled separately. To include net dividends in your result, you can add dividend income to your proceeds figure manually or conceptually adjust your sell price.
- Market impact and slippage ignored: The tool assumes you can trade at the buy and sell prices you enter and does not attempt to estimate slippage, partial fills, or spreads.
Because of these simplifications, the output should be treated as an estimate rather than an exact statement of after-tax, after-all-fees profitability. For precise accounting or tax reporting, rely on official broker statements or a qualified professional.
Common Edge Cases and How to Handle Them
Many traders have situations that do not fit neatly into a simple buy-then-sell pattern. Here are a few common edge cases and practical ways to work with them using this calculator:
- Short selling: For a short sale, you can treat your short-sale price as the “sell” price and your eventual buy-to-cover price as the “buy” price. Enter your borrow or transaction fees in the commission fields as appropriate. A positive result then represents a profitable short.
- Fractional shares: You can enter fractional share quantities (e.g., 12.5 shares) if your broker allows them. The formulas work the same way as with whole shares.
- Dividend-paying stocks: If you received dividends while holding the stock and want them reflected in your overall return, you can add the net dividend amount to your proceeds when you interpret the result, or adjust the sell price to include the dividend on a per-share basis.
- Multiple trades over time: For a position built up through several buys and sold in several lots, you can approximate results by first calculating your average cost per share and total number of shares, then entering those into the calculator. Alternatively, run the calculation separately for each round trip and aggregate the outcomes.
FAQ
Does this calculator include taxes?
No. Taxes are not included automatically. If you want to factor in an estimated tax cost, you can add it to your commission values so that the total cost reflects those amounts.
How do I find my break-even stock price?
Your break-even sell price is the price at which your net profit is zero. Set commissions as needed, then adjust the sell price in the calculator until the net profit or loss field is approximately zero. That sell price is your break-even point.
How is ROI different from annualized return?
ROI in this tool is a simple percentage of your original cost and does not account for how long you held the position. Annualized return adjusts the percentage to a yearly rate. To evaluate trades held for very different time periods, annualized figures are more comparable than simple ROI.
Can I use this for short selling?
Yes, with a small adjustment in interpretation. Enter your short entry price as the sell price and your buy-to-cover price as the buy price. A positive profit output means your short trade was profitable.
Can I rely on this for official records?
No. The calculator is for planning and educational purposes only. For official records, tax filings, or regulatory reporting, use your broker statements and consult with a qualified professional if needed.