Stock Profit Calculator
This calculator estimates profit, return on investment (ROI) and annualized return for a single stock trade. It supports commissions, dividends, a simple stock-split factor and a user-provided tax-rate assumption.
Use the basic mode for a quick result and the detailed mode for an estimated post-tax result. Results are for informational purposes and not tax, legal or investment advice.
Adds a simple, user-configurable tax estimate on realized gains and reports net profit and net ROI. Use this as an estimate only; tax laws vary and actual calculations may require tax lot-level data.
Inputs
Results
Net profit after estimated tax (USD)
$161.50
Estimated tax on gain (USD)
$28.50
Net return on investment
16.07%
Annualized return after tax (CAGR)
16.07%
| Output | Value | Unit |
|---|---|---|
| Net profit after estimated tax (USD) | $161.50 | USD |
| Estimated tax on gain (USD) | $28.50 | USD |
| Net return on investment | 16.07% | % |
| Annualized return after tax (CAGR) | 16.07% | % |
Visualization
Methodology
Calculations follow standard financial math for trade cash flows: total cost = buy price × shares + buy fees; total proceeds = sell price × shares − sell fees; dividends are added to proceeds before computing profit and returns.
Annualized return is computed using a compound annual growth rate (CAGR) approximation: (ending value / beginning value)^(1 / years) − 1. Tax estimates are a simple percentage applied to an estimated taxable gain and do not replace tax-professional calculations.
Worked examples
Example: Buy 100 shares at $10, sell at $12 after 365 days, $5 commissions each side, no dividends. Gross profit ≈ $100, ROI ≈ 10%, annualized ≈ 10%.
Example with tax: Same trade with a 15% tax rate on estimated gains → estimated tax ≈ $15, net profit ≈ $85.
Further resources
Expert Q&A
How accurate are results?
Results use standard arithmetic and are validated against unit tests. Accuracy for floating-point arithmetic follows typical double-precision behavior. This tool provides estimates; rounding, broker-specific fee structures, tax rules and lot accounting can change real outcomes.
Does the calculator handle multiple buy/sell lots or partial sales?
No. This calculator models a single aggregated trade (one buy block, one sell block). For multiple lots or partial sales, you should run multiple calculations or use accounting that supports per-lot basis.
Is the tax estimate exact?
No. Tax is a simple percentage applied to an estimated taxable gain. It does not model short-term vs long-term rates, exemptions, deductions or jurisdictional specifics. Consult a tax professional for precise tax treatment.
Why is the annualized return sometimes undefined or extreme?
Annualized return uses the ratio of ending to starting value and exponentiation by 1/years. Very small or negative starting values, zero holding period, or negative net proceeds can produce undefined, very large, or complex values. The tool requires a positive total cost and a holding period greater than zero for a meaningful CAGR.
Sources & citations
- National Institute of Standards and Technology (NIST) — https://www.nist.gov
- International Organization for Standardization (ISO) — https://www.iso.org
- Institute of Electrical and Electronics Engineers (IEEE) — https://www.ieee.org
- U.S. Securities and Exchange Commission (SEC) — Investor guidance — https://www.sec.gov
- Internal Revenue Service (IRS) — Tax guidance — https://www.irs.gov