Stock Profit Calculator

Stock profit (or loss) on a closed trade is the difference between what you received when selling and what you paid to buy, including commissions and fees. Cost basis = shares × buy price (+ buy-side fees). Proceeds = shares × sell price − sell-side fees. Profit = proceeds − cost basis. Return % = profit ÷ cost basis × 100.

Use this when planning an exit, reviewing a completed trade, or comparing brokers with different fee structures. It covers a simple single-lot purchase and full sale — not partial sells, wash sales, or multiple purchase dates. For tax reporting, the IRS cares about holding period (short-term vs long-term capital gains) and your actual cost basis records.

Example: buy 50 shares at $142.50 ($7,125 cost basis), sell at $168.20 with $0 fees. Proceeds = $8,410. Profit = $1,285. Return ≈ 18.0%. Add any commission to fees if both sides charge. Capital gains tax depends on hold time and income — consult a tax professional.

Losses subtract symmetrically. Buy 100 shares at $50 ($5,000), sell at $42 ($4,200 proceeds) → −$800 loss, −16% return. Loss harvesting for taxes requires understanding wash-sale rules this tool does not model.

Fees matter most on small trades. A $5 commission on a $500 trade is 1% each way — 2% round trip before price movement. Commission-free brokers shift cost to payment-for-order-flow spreads instead.

Return percentage uses cost basis as denominator, not proceeds. A $1,000 profit on $5,000 invested is 20% even though proceeds were $6,000.

Worked example with fees: 200 shares, buy $25, sell $28, $9.99 commission each side. Cost basis = $5,009.99. Proceeds = $5,590.01. Profit ≈ $580. Return ≈ 11.6%. Without fees, profit would be $600 (12%).

Multiple purchase lots need weighted average cost or specific lot identification at sale. Enter one blended buy price here or calculate each lot separately.

Not tax or investment advice. Broker 1099-B forms may differ slightly from your records — reconcile before filing.

Wash-sale rules defer loss recognition if you repurchase the same or substantially identical security within 30 days before or after the sale — IRS reporting may adjust basis.

Corporate actions (splits, spinoffs) adjust cost basis — check your broker’s cost basis after splits rather than using the original purchase price alone.

Short sales and options strategies need different P&L math — this tool covers simple long stock only.

Gifted and inherited stock use different basis rules (step-up at death for inherited shares) — this calculator assumes you purchased at the entered buy price.

Fractional share platforms may show proceeds with rounding differences — reconcile to 1099-B totals at tax time.

Holding period clock starts at purchase and ends at sale for long-term capital gains — track purchase date separately when using average cost across multiple lots.

Mark-to-market on open positions is unrealized gain, not profit — this tool applies only when you enter a completed buy and sell; open trades need current price vs basis instead.

Short sales (sell borrowed shares) invert P&L logic — this calculator covers long positions only; short cover buys are a different cost-basis workflow.

Corporate actions like spinoffs allocate basis across new tickers — broker-provided basis adjustments should replace simple buy-minus-sell math after complex events.

Keep trade confirmations for wash-sale and basis audits — broker summaries help but original tickets document dates for long-term versus short-term classification.

Pre-tax profit here excludes state capital gains taxes — high-tax states can take an additional slice on top of federal long-term or short-term rates after you sell.

Gifted stock inherits donor basis in many cases — recipient profit math uses carryover basis, not fair market value on gift date, unless estate step-up rules apply.

Round-trip trades in taxable accounts should match 1099-B totals before filing each tax season.