Stock Gain Percentage Calculator 2026

Stock Gain Percentage Calculator

Enter your purchase and sale prices per share, along with any broker commissions, to calculate your total gain or loss, percentage return, and break-even sale price.

How Stock Gain Percentage Works

The percentage gain or loss on a stock trade tells you how much your investment has grown or shrunk relative to what you paid. It is the single most useful measure for comparing one trade against another, regardless of how much money you put in.

The basic formula is straightforward: subtract the purchase price from the sale price, divide by the purchase price, and multiply by 100. If you bought shares at £5.00 and sold at £6.50, your gain per share is £1.50 and your percentage gain is (£1.50 ÷ £5.00) × 100 = 30%.

In practice, broker commissions eat into your return. Most UK investment platforms charge a flat fee per trade — typically between £5.95 and £11.95 — rather than a percentage. The calculator above deducts buying and selling commissions from your total to give a true net profit and an accurate return on investment figure.

Your return on investment (ROI) tells you how much you gained or lost for every pound you put in. The calculator works this out as: net profit divided by your total initial outlay (purchase cost plus buying commission), multiplied by 100. This lets you compare trades of different sizes fairly — a £50 profit on a £500 investment (10% ROI) is a better return than a £50 profit on a £5,000 investment (1% ROI).

The break-even sale price is the minimum price per share you would need to sell at to recover your entire investment plus all fees. It is useful for setting limit orders or deciding whether to hold or sell at the current market price.

One important distinction is between total percentage gain and annualised return. A 20% gain over five years is very different from 20% over three months. To compare investments held for different periods, investors often annualise the return using the compound annual growth rate (CAGR) formula. This calculator focuses on total percentage gain for a single buy-and-sell trade, which is the right starting point for evaluating any individual position.

Example Stock Gain Calculations

Scenario 1: A Profitable FTSE 250 Trade

You bought 200 shares at £3.45 each, costing £690.00, and later sold them at £4.80 each for £960.00, paying £11.95 commission each way. The gain per share is £4.80 − £3.45 = £1.35, giving a total gain of 200 × £1.35 = £270.00. The percentage gain is (£1.35 ÷ £3.45) × 100 = 39.13%. Total fees come to £11.95 + £11.95 = £23.90, leaving a net profit of £270.00 − £23.90 = £246.10. Your ROI after fees is £246.10 ÷ £701.95 (purchase cost plus buying commission) × 100 = 35.06%.

Scenario 2: A Losing Trade on a Falling Share

You bought 50 shares at £12.60 each, costing £630.00, but the price fell and you sold at £9.85 each for £492.50, paying £5.99 commission each way. The loss per share is £9.85 − £12.60 = −£2.75, giving a total loss of 50 × −£2.75 = −£137.50. The percentage loss is (−£2.75 ÷ £12.60) × 100 = −21.83%. Total fees of £5.99 + £5.99 = £11.98 deepen the loss to −£137.50 − £11.98 = −£149.48. Your ROI after fees is −£149.48 ÷ £635.99 (purchase cost plus buying commission) × 100 = −23.50%.

Scenario 3: A High-Volume Penny Stock Trade

You bought 10,000 shares at £0.15 each, costing £1,500.00, and sold them at £0.22 each for £2,200.00, paying £9.95 commission each way. The gain per share is £0.22 − £0.15 = £0.07, giving a total gain of 10,000 × £0.07 = £700.00. The percentage gain is (£0.07 ÷ £0.15) × 100 = 46.67%. Total fees are £9.95 + £9.95 = £19.90, leaving a net profit of £700.00 − £19.90 = £680.10. Your ROI after fees is £680.10 ÷ £1,509.95 (purchase cost plus buying commission) × 100 = 45.04%.

Understanding Your Returns

What Affects Your Stock Returns

Several factors beyond the share price movement affect the percentage return on a stock trade. Understanding these helps you set realistic expectations and avoid common mistakes.

Broker fees have the biggest impact on smaller trades. A £11.95 flat fee on a £100 trade is an immediate 11.95% drag on your return, while the same fee on a £10,000 trade costs just 0.12%. This is why experienced investors often prefer to make fewer, larger trades rather than many small ones.

Stamp Duty Reserve Tax (SDRT) applies when you buy shares listed on a UK exchange. The rate is 0.5% of the purchase value, collected automatically by your broker. This calculator does not include SDRT separately — if your broker charges it within the commission, it is already captured. If not, you can add it to the buying commission field manually.

Capital Gains Tax (CGT) may apply when you sell shares at a profit outside an ISA or pension wrapper. In the 2026/27 tax year, the CGT annual exempt amount is £3,000. Gains above this are taxed at 18% (basic rate) or 24% (higher rate). Our Capital Gains Tax Calculator can help you work out your liability.

Currency risk affects returns on shares denominated in foreign currencies. If you bought US shares and the pound strengthened against the dollar between your buy and sell dates, your sterling return will be lower than the dollar return — even if the share price rose.

Tips for Tracking Your Portfolio

Calculating individual trade returns is a starting point, but your overall portfolio performance tells the real story. Here are a few practical points for UK investors.

Keep a simple spreadsheet or use your broker’s built-in reporting to record every trade: date, price, shares, fees and total cost. This makes it straightforward to calculate your aggregate return at the end of each tax year and simplifies your Self Assessment if you owe Capital Gains Tax.

Compare your returns against a benchmark. The FTSE All-Share index is the standard UK benchmark for equity returns. If your stock picks consistently underperform the index after fees, a low-cost index tracker fund inside a Stocks and Shares ISA may deliver better results with less effort.

Avoid fixating on unrealised gains. A share price increase is only a return when you sell. Paper profits can disappear quickly, and the tendency to hold winning positions too long is one of the most common behavioural biases in investing.

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