Investment return: instructions and assumptions
Understand your inputs, results and the assumptions behind the calculation.
Price gains and actual returns are different
Even if the selling price is 20% above the purchase price, fees make the actual return lower. This assumes one purchase and one sale, with the same percentage fee on both. Enter the current price as the selling price to estimate an exit result.
Sale proceeds = selling price × shares × (1 − fee rate)
Net profit = sale proceeds − total purchase cost
Return = net profit ÷ total purchase cost × 100
Worked example
Suppose you buy 100 shares at KRW 50,000 and sell all at KRW 60,000. The 0.015% fee applies separately to the purchase and sale.
| Item | Result |
|---|---|
| Purchase fee | KRW 750 |
| Sale fee | KRW 900 |
| Total purchase cost | KRW 5,000,750 |
| Sale proceeds | KRW 5,999,100 |
| Net profit / return | KRW 998,350 / about 19.96% |
When to use this tool
- Change a target selling price to see your profit after costs.
- Compare different fee rates to understand their impact.
- See what you would receive when selling at a loss.
What is excluded
Transaction taxes, capital gains tax, dividends, FX fees and exchange-rate changes are excluded. Select KRW or USD and enter every price in that currency. Switching currency keeps the numbers unchanged; there is no automatic FX conversion. Different buy/sell fee rules or minimum fees can change actual settlement. KRW is displayed in whole won; USD has two decimals. Buying 100 shares at USD 50 and selling at USD 60, with a 0.015% fee on each side, gives USD 998.35 net profit.
What does a negative return mean?
Sale proceeds are below the purchase cost including fees. Even at an unchanged price, fees can produce a loss.
Can I handle multiple purchases and partial sales?
This tool assumes one purchase and one sale. Use the average-cost calculator for multiple purchase prices. It is not a transaction ledger for individual fees or partial-sale accounting.
Related reading: Return needed to recover a loss