Simple definition
A capital loss is what happens when you sell an investment for less than you paid. It's the opposite of a capital gain. Say a stock you bought drops and you sell it — the difference between your purchase price and the lower sale price is your loss. It only counts once you actually sell; a drop you haven't sold into is just a paper loss. Real losses can help lower your taxes.
Why it matters
Losses sting, but the tax code offers a small consolation: capital losses can offset capital gains and even a limited amount of regular income, lowering your tax bill. Understanding this turns a bad investment into at least a partial tax break rather than a total write-off.
Real-life example
You buy $6,000 of a stock and later sell it for $4,000, taking a $2,000 capital loss. That loss can cancel out $2,000 of gains from another winning investment that year, so you owe tax on less of your overall profit.
Formula
Capital loss = cost basis − sale price
Common mistakes
- Selling and rebuying the same investment too fast, triggering the wash-sale rule.
- Forgetting to report losses and missing a chance to lower your taxes.
- Selling good investments in a panic just to book a loss.
- Overlooking that losses first offset gains before reducing ordinary income.
Pro tips
- Use losses to offset gains first, then a limited amount of ordinary income.
- Carry extra losses forward to future tax years if they exceed the annual limit.
- Avoid the wash-sale rule by not rebuying the same security within 30 days.
- Keep good records of your cost basis so your loss is calculated correctly.
Related Money Dictionary terms
- Capital GainThe profit you make when you sell an investment for more than you paid for it.
- Tax-Loss HarvestingSelling investments at a loss on purpose to offset taxable gains and lower your tax bill for the year.
- Cost BasisThe original amount you paid for an investment, used to figure out your taxable gain or loss when you sell.
- Wash SaleSelling an investment at a loss and rebuying it within 30 days, which cancels the tax benefit of that loss.
- Capital Gains TaxThe tax you owe on the profit from selling an investment for more than you paid.
- StockA share of ownership in a company that you can buy and sell, giving you a small stake in its profits and growth.
Frequently asked questions
Can a capital loss lower my taxes?
Yes. Losses first offset your capital gains dollar for dollar. If your losses are bigger than your gains, you can use a limited amount to reduce your regular income each year, and carry the rest forward to future years. It won't erase a bad investment, but it softens the blow at tax time.
What is the wash-sale rule?
It stops you from claiming a loss if you sell an investment and buy the same or a nearly identical one within 30 days before or after. The IRS disallows the loss for tax purposes in that window. To keep the tax benefit, wait more than 30 days or buy something clearly different.
Do I have to sell to claim a loss?
Yes. A drop in value you haven't sold is only a paper loss and doesn't count on your taxes. You have to actually sell to realize, or lock in, the loss before it can offset gains or income. That's why some investors deliberately sell losers near year-end to capture the tax benefit.
Knowing what Capital Loss means is knowledge — the first half. A brick gets placed when you act on it: review your investments for a loser you could sell to offset this year's gains at tax time.
Also builds: Investing
Sources & references
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Plain-English education — not personalized legal, tax, or investment advice.