Stock Profit/Loss Calculator

Stock trade profit and loss calculation is essential for evaluating trade performance and for accurate tax reporting. The calculation differs depending on whether you’re doing a simple buy-sell, dealing with short sales, factoring in dividends, or calculating cost basis across multiple purchases.

Formulas: Gross Profit/Loss = (Sell Price − Buy Price) × Shares Net Profit/Loss = Gross P/L − Total Commissions − Fees Return % = (Net P/L ÷ Total Cost) × 100 Annualized Return % = ((1 + Return%)^(365 ÷ Days Held) − 1) × 100 Break-even Price = (Buy Price × Shares + Commissions) ÷ Shares

What each variable means:

• Buy Price: the price paid per share (cost basis per share)
• Sell Price: the price received per share at sale
• Shares: total number of shares in the transaction
• Commissions: brokerage fees (many brokers now charge $0, but some charge $4.95–$6.95 per trade)
• Cost Basis: the total amount invested, used for tax purposes

Tax implications (US):

• Short-term capital gain (held ≤ 365 days): taxed as ordinary income (10–37%)
• Long-term capital gain (held > 365 days): taxed at preferential rates (0%, 15%, or 20% depending on income)
• The difference can be enormous: a $10,000 gain taxed short-term at 32% = $3,200 tax. Long-term at 15% = $1,500 tax.

Worked example: Buy: 100 shares at $45.20 on March 1, 2023 (cost = $4,520) Sell: 100 shares at $67.85 on November 15, 2023 ($6,785) Commission: $0 (zero-commission broker)

Gross profit = ($67.85 − $45.20) × 100 = $22.65 × 100 = $2,265 Net profit = $2,265 − $0 = $2,265 Return % = $2,265 ÷ $4,520 × 100 = 50.1% Days held = 259 days Annualized return = ((1.501)^(365/259) − 1) × 100 = 73.1% annualized Tax rate: short-term (held 259 days < 365) — taxed as ordinary income

Break-even price (if commission were $9.95 total): ($4,520 + $9.95) ÷ 100 = $45.30/share