Stock Average Price Calculator
Enter price and quantity per buy — get weighted-average cost, break-even price, and live P&L.
How to Use
"+ Add buy" creates a new row. Fill in price (KRW) and quantity per buy. Fees are computed automatically.
Type the current price to see P&L and ROI. The numbers include the 0.2% sell tax and 0.015% buy/sell fees so they reflect realized return on sale.
Average cost, total invested (incl. fees), break-even price (minimum sell price to recover cost), and — with current price — P&L and ROI. Useful for planning and DCA simulations.
FAQ
How is the average price computed?
Average = Σ(price × quantity) / Σ(quantity). e.g., 10,000 × 10 + 8,000 × 10 = 180,000 / 20 = 9,000 average.
What is the break-even price?
Minimum sell price at which you do not lose money. = average × (1 + buy fee + sell tax + sell fee). Korean standard: 0.015% buy + 0.2% sell tax + 0.015% sell fee → average × ~1.0023. A 10,000 average needs ~10,023 to break even.
About the Korean sell tax?
Korea charges a 0.18% securities-transaction tax on sale (both KOSPI and KOSDAQ as of 2026). This tool uses 0.2% conservatively. No capital-gains tax for non-major-shareholder individuals (Korea 2026).
About buy/sell fees?
Brokerage fees vary; this tool uses 0.015% for both buy and sell as a reasonable average. Non-face-to-face accounts and fee-waiver promotions may be lower. Check your broker.
How to simulate "averaging down"?
Add your existing buy as the 1st row, then a hypothetical additional buy (price + quantity) as the 2nd row. The average drops accordingly, and break-even moves down — useful for deciding when to average in.
Is my input sent to a server?
No. All computation runs in your browser; inputs are never sent over the network.
