Why is my profit lower than the price difference?

Because buy and sell commissions plus the transaction tax are deducted. On a 20% gain the costs above consume about 1.2 percentage points, and they matter far more on short holding periods.

What return does the percentage show?

Net profit divided by the amount invested, so it already includes fees and tax. That is the figure to compare with a savings rate or an index fund.

How do I include dividends?

Add the gross dividend to the sell amount, or to profit, before tax. This calculator only covers capital gains from the price change.

Stock Profit Calculator - Your Calculator

Calculate profit rate and profit from buy/sell prices.

Buy Price Sell Price Quantity (shares) Fee Rate (%)

Why Fees and Taxes Matter

When calculating stock profit or profit rate, fees and taxes must be considered. Ignoring them may lead to selling at a lower-than-expected profit or even a loss.

How to Calculate Profit Amount

Profit amount is the sell amount minus the buy amount, buy commission, sell commission, and trade tax.

Sell Amount − Buy Amount − Buy Commission − Sell Commission − Trade Tax

How to Calculate Profit Rate

Profit rate is the profit amount divided by the buy amount, expressed as a percentage.

(Sell Amount − Buy Amount − Buy Commission − Sell Commission − Trade Tax) ÷ Buy Amount × 100

How to Calculate Buy Commission

Buy Price × Quantity × Fee Rate

How to Calculate Sell Commission

Sell commission is the sell total multiplied by the fee rate, plus the trade tax. (No tax if profit is negative.)

(Sell Price × Quantity × Fee Rate) + (Sell Price × Quantity × Trade Tax Rate)

Stock Profit Calculation Formulas

Profit = (Sell Price − Buy Price) × Qty − Commission − Trade Tax

Profit Rate = Profit ÷ Buy Total × 100

Fees and Taxes

Buy Commission: Buy Total × Fee Rate

Sell Commission: Sell Total × Fee Rate

Trade Tax: Sell Total × 0.18% (2024, KOSPI 0.05% + Agriculture Tax 0.15%)

Worked examples

Buying 100 shares at $50 and selling at $60 gives a $1,000 gain before costs; with 0.015% fees and 0.18% sale tax the net profit is about $987.55, a 19.75% return.

Buying 100 shares at $80 and selling at $70 turns the same costs into a loss of about $1,014.85, a return of −12.69%.

What the result assumes

Costs are charged on both trades plus a transaction tax on the sale, so the net figure is always below the naive price difference. Each fill is treated as one trade at a single price and no dividends, currency changes or partial sales are modelled. Commission is entered as a percentage, not as a flat fee, so check your broker schedule before relying on the number.

Frequently asked questions

Why is my profit lower than the price difference?: Because buy and sell commissions plus the transaction tax are deducted. On a 20% gain the costs above consume about 1.2 percentage points, and they matter far more on short holding periods.
What return does the percentage show?: Net profit divided by the amount invested, so it already includes fees and tax. That is the figure to compare with a savings rate or an index fund.
How do I include dividends?: Add the gross dividend to the sell amount, or to profit, before tax. This calculator only covers capital gains from the price change.