Investment P&L Calculator
What Is an Investment P&L Calculator?
An investment P&L calculator helps you figure out your true average buy price when you purchase an asset at multiple price points. It then estimates your net profit or loss after exchange fees and capital gains tax — so you know exactly what you would take home if you sold today.
Enter each purchase, set a sell price, and see average cost, ROI, and net profit update instantly.
How to Use This Calculator
- Enter purchases: For each buy, type the number of shares (or coins) and the price you paid.
- Add rows: Click Add Another Purchase for every additional entry point.
- Set sell price: Enter the price at which you plan to sell on the right panel.
- Adjust fees and tax: Match the exchange fee % and capital gains tax rate to your situation.
- Review results: Check true average cost, net profit/loss, and ROI percentage.
Average Cost & Profit Formulas
Average Cost = Total Cost Basis ÷ Total Shares
Net Profit = (Shares × Sell Price) − Cost Basis − Fees − Tax
ROI = (Net Profit ÷ Cost Basis) × 100
Worked Example
You bought 10 shares at $150 and 5 shares at $120, planning to sell at $180 with a 0.1% fee and 15% capital gains tax:
Total cost = (10 × $150) + (5 × $120) = $2,100
Total shares = 15
Average cost = $2,100 ÷ 15 = $140.00/share
Gross revenue = 15 × $180 = $2,700
Net profit after fees and tax ≈ $505.92 (ROI ≈ 24.1%)
Frequently Asked Questions
How do I calculate profit on a stock sale?
Net profit = (shares × sell price) − total cost basis − exchange fees − capital gains tax. Enter each purchase to get your blended average cost, then set a sell price to see take-home profit.
How is average cost basis calculated?
Add up total invested across all purchases and divide by total shares. Formula: Average Cost = Total Cost Basis ÷ Total Shares. Example: ($1,500 + $600) ÷ 15 shares = $140/share.
What does it mean to average down?
Buying more shares after the price drops lowers your average cost per share, making it easier to reach breakeven when the price rebounds.
What is ROI in this calculator?
ROI = (Net Profit ÷ Total Cost Basis) × 100. It shows your return after fees and taxes relative to what you invested — not just the price change.
How are exchange fees and taxes handled?
Fees are deducted on both buy and sell sides. Capital gains tax applies only to positive profits. Adjust both percentages to match your broker and tax bracket.
Does this work for crypto and stocks?
Yes — the math is identical. Enter each buy as shares or coins at the price you paid, whether on a brokerage or crypto exchange.
What is my breakeven sell price?
Breakeven is where net profit hits zero after fees and tax. Raise the sell price in the calculator until net profit reaches $0 — that is your minimum exit price.
Is this the same as dollar-cost averaging (DCA)?
Related but different. DCA is a strategy of buying at regular intervals. This calculator measures the result — your blended average cost after multiple purchases at different prices.
Knowing your true average cost and net profit helps you sell with confidence instead of guessing. Use this free calculator to plan your exit, then consult a tax professional for your specific reporting requirements.