What it means
Every asset you hold for investment or long-term use has a cost basis (the original price you paid, plus certain costs of buying it). When you sell, the difference between the sale proceeds and that cost basis is your capital gain or loss.
If the number is positive, you have a gain; if negative, you have a capital loss. Tax authorities treat capital gains differently from salary or trading profits.
Many countries tax them at a separate rate, and some give a lower rate when the asset was held for a longer period. The rates and holding period rules are set by each tax authority and change over time, so always check the current rules before planning a sale.
An unrealised gain is the increase in value of an asset you still own, and it is normally not taxed. A realised gain arises only when you sell or otherwise dispose of the asset.
That timing gap is why investors and business owners often think carefully about when to sell, because the tax bill falls in the year the gain is realised. Capital gains matter well beyond the stock market.
A company that sells a building, a founder who sells shares in their start-up, and a landlord who sells a rental flat all have to work out a gain. Selling costs such as legal fees and agent commissions can usually be deducted, and improvements that added lasting value can often be added to the cost basis.
Finance teams also need to separate capital gains from operating profit when reporting. A one-off gain on selling equipment can make a year look far more profitable than the underlying business really was.
Analysts therefore strip such items out when judging how the core operations are performing.
In practice
Real-world examples
Example 1
A software founder sells a 10% stake in her company to an investor for $800,000. Her original cost for those shares was $50,000. Her capital gain is $750,000, before any allowable costs and tax.
Example 2
A manufacturing company sells a warehouse that it bought years ago for $1,200,000 and has since depreciated to a book value of $900,000. It sells the building for $1,500,000. The accounting gain is $600,000 over book value, and the tax calculation may use a different base, so the finance team prepares both figures.
Example 3
A retired teacher sells a portfolio of index fund units for $90,000 that cost her $60,000 over the years. Her gain is $30,000. She plans the sale for a year when her other income is low, in case the tax system lets her pay a lower rate.
Think of it
Capital gains are profits from selling investments-the difference between what you paid and what you got.
Formula
Calculation
Capital gain = Sale proceeds - Selling costs - Cost basis
Worked example: a business owner bought shares in a private company for $40,000 and later sold them for $55,000, paying $500 in broker fees.
Step 1: Start with the sale proceeds of $55,000.
Step 2: Deduct the selling costs: $55,000 - $500 = $54,500.
Step 3: Deduct the cost basis: $54,500 - $40,000 = $14,500.
Capital gain = $55,000 - $500 - $40,000 = $14,500.
If the applicable tax rate on the gain were 15% (an assumed rate for illustration only), the tax would be $14,500 x 15% = $2,175, leaving the owner with $12,325 of gain after tax.Case study
Seen in the real world
Brightwater Crafts is an illustrative, fictional furniture maker that owns the workshop it operates from. After ten years the owners decide to sell the building for $2,000,000 and rent a smaller space. The building cost $800,000 when bought, and the owners spent $100,000 on a new roof and extension.
The finance manager adds the improvements to the original price to reach a cost basis of $900,000. After $40,000 of agent and legal fees, the capital gain is $2,000,000 - $40,000 - $900,000 = $1,060,000. She sets aside a tax provision before the owners plan any spending of the sale proceeds.
The lesson in this illustrative story is that the headline sale price is not the profit. Costs, improvements and tax all sit between the cheque and the money the business can actually use.
Watch out
Common mistakes
- Calculating the gain from the sale price alone and forgetting to deduct the original cost basis and selling costs.
- Treating an unrealised gain as taxable income, when in most systems tax arises only once the asset is sold.
- Ignoring the holding period, even though in many tax systems a longer holding period earns a lower rate.
Questions
People also ask
Is a capital gain the same as profit?
It is a profit on selling an asset, but it is reported and taxed separately from the profit a business earns from its regular trading.
Can I offset a capital gain with a loss?
Usually yes, since most tax systems let you net capital losses against capital gains, although the exact rules vary by country.
Do I pay tax if I reinvest the proceeds?
Often yes, because tax normally depends on the sale itself, though some systems offer specific relief for particular reinvestments.
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