A stock profit calculator computes the true net return on any equity trade by accounting for the actual sell price, your cost basis, and the regulatory fees that reduce gross proceeds on every transaction. Most traders mentally subtract buy from sell and call it profit — but SEC fees, FINRA charges, and commissions shift the real number. The calculator above handles all of that instantly.
How to Use
| Input | What to Enter | Example |
|---|---|---|
| Shares Purchased | Total shares bought across all tranches | 200 |
| Cost Basis Per Share | Average purchase price; use blended basis for multiple buys | $170.25 |
| Sell Price Per Share | Price at time of sale | $181.00 |
| Shares Sold | Shares in this exit; enter less than held for a partial exit | 100 |
| Commission | Round-trip brokerage fee; $0 for most retail accounts | $0.00 |
The output shows net profit in dollars, percentage return on the capital deployed in this exit, and your break-even sell price. For partial exits, only the shares sold factor into the return calculation — the remaining position’s unrealized gain is tracked separately.
Formula Explained
Net Profit = (Shares Sold × Sell Price)
− (Shares Sold × Cost Basis Per Share)
− SEC Fee
− FINRA TAF
− Commission
SEC Section 31 fee equals $8.00 per $1,000,000 of gross sell proceeds (2024 rate). On a $36,200 sale, that is $0.29 — small individually but meaningful at scale. The fee applies to every equity sell order regardless of broker.
FINRA Trading Activity Fee (TAF) is approximately $0.000145 per share sold, capped at $7.27 per trade. Selling 200 shares generates a $0.03 TAF; selling 50,000 shares hits the $7.27 cap.
Commission varies by broker. Fidelity, Schwab, and Robinhood have charged $0 per trade since 2019. Active traders using Interactive Brokers’ tiered per-share pricing pay approximately $0.005 per share, so a 200-share trade costs $1.00 round-trip.
Break-even price is the minimum sell price that produces $0 net profit. It equals cost basis plus total fees divided by shares sold. Knowing this number prevents exits that appear profitable but actually lose money after fees.
Example Calculations
Scenario 1: AAPL Average-In Position, Full Exit
A trader builds a 200-share AAPL position across three orders: 100 shares at $168.00, 50 shares at $171.00, and 50 shares at $174.00.
Blended cost basis: ((100 × 168) + (50 × 171) + (50 × 174)) / 200 = 34,050 / 200 = $170.25 per share
Total invested: $34,050. The trader sells all 200 shares at $181.00 on Schwab (zero commission):
- Gross proceeds: 200 × $181.00 = $36,200
- Gross profit: $36,200 − $34,050 = $2,150
- SEC fee: $36,200 × 8 / 1,000,000 = $0.29
- FINRA TAF: 200 × $0.000145 = $0.03
- Net profit: $2,149.68 — a 6.31% return on $34,050 invested
The $0.32 in regulatory fees is negligible here, but a trader who runs 5 positions of this size per week generates roughly $83 in regulatory costs annually — worth tracking in a trade journal.
Scenario 2: MSFT Swing Trade, Partial Exit
A swing trader buys 200 shares of MSFT at $415.00 ($83,000 invested) and sells 100 shares at $428.00 to lock in partial gains.
- Gross proceeds on 100 shares: $42,800
- Cost of 100 shares: $41,500
- SEC fee: $42,800 × 8 / 1,000,000 = $0.34
- FINRA TAF: 100 × $0.000145 = $0.015
- Net profit on the partial exit: $1,299.65 (3.13%)
The remaining 100 shares still carry the $415.00 cost basis. Their unrealized gain at $428.00 is $1,300 gross — tracked separately until closed.
Scenario 3: Stock Split Adjustment
NVDA underwent a 10-for-1 split in June 2024. A trader who bought 10 shares at $875.00 pre-split now holds 100 shares with an adjusted cost basis of $87.50 per share (not $875.00). Entering the pre-split price into a profit calculator without adjustment produces a false loss. Always use the post-split adjusted cost basis — most brokers restate this automatically in your account history.
When to Use This Calculator
- Before deciding to exit: Compare net return at your target sell price against your actual cost basis, not a rough mental estimate.
- Partial exit planning: Determine whether selling half a position locks in a meaningful return while keeping the remainder’s upside.
- Comparing average-in entries: After scaling into a position across multiple prices, compute the blended basis before you know whether the trade is profitable.
- Tax lot selection: Run the calculation for each available lot (FIFO, LIFO, specific identification) to understand which produces a short-term versus long-term gain — the difference between a 37% and a 15% tax rate on the same dollar profit.
- Commission sensitivity: If you trade on per-share pricing, model how commission affects net return at different position sizes to find the minimum size worth trading.
Logging Results in a Trade Journal
The output of this calculator — entry price, cost basis, exit price, shares, fees, net profit, and percentage return — forms the core data set of a trade log. Entering these fields after every closed trade enables pattern analysis that a one-off calculation cannot: which setups produce consistent 5%+ returns, which exit strategies leave money on the table, and whether per-share fees are eroding edge at smaller position sizes. JournalPlus imports broker trade history automatically and computes blended cost basis, net return after fees, and tax lot attribution without manual entry.
Related Tools
- Stock Average Calculator — Computes the blended cost basis when you add to a position at multiple prices; use it to feed the correct cost basis into this profit calculator.
- Risk/Reward Calculator — Maps the ratio between potential profit and planned stop loss before entry, complementing the after-the-fact profit calculation here.
- R-Multiple Calculator — Expresses trade outcome as a multiple of initial risk; combining it with net profit data reveals whether large winners justify small winners in your strategy.
Frequently Asked Questions
How do you calculate profit on a stock trade?
Net profit equals gross proceeds (shares sold times sell price) minus cost of shares sold (shares sold times cost basis per share) minus SEC fee minus FINRA TAF minus commission. For a single-lot purchase, cost basis is simply your buy price. For multiple purchases, use the blended average: total dollars paid divided by total shares bought.
What is the SEC fee on stock trades?
The SEC Section 31 transaction fee is $8.00 per $1,000,000 of gross sale proceeds as of 2024. It applies to every sell order on US exchanges regardless of broker. On a $10,000 sale, the fee is $0.08; on a $500,000 sale, it is $4.00. The fee is collected by your broker at settlement.
What is the FINRA TAF?
The FINRA Trading Activity Fee (TAF) is approximately $0.000145 per share sold and is capped at $7.27 per trade. It applies to equity sell orders and is assessed in addition to the SEC fee. A 500-share sale generates $0.0725 in TAF; a 60,000-share sale hits the $7.27 cap.
How do you calculate return on a partial exit?
Divide net profit on the sold shares by the cost of those shares only. If a 200-share position was built at a $170.25 blended basis and 100 shares are sold at $181.00, the return is ($1,075 − fees) / $17,025 — not divided by the full $34,050 position cost. The remaining 100 shares are an open position and their return is calculated separately when closed.
Does average-in cost basis change the break-even price?
Yes. Each additional purchase at a different price shifts the blended basis and therefore the break-even. Adding shares below your original entry lowers the break-even; adding above it raises the break-even. The break-even sell price equals total cost basis plus all sell-side fees, divided by shares sold — and it changes with every new purchase tranche.
