A short-term capital loss deduction works in a fixed order: the loss first cancels out any short-term capital gains you had that year, then offsets long-term capital gains, and only after that reduces up to $3,000 of your ordinary income ($1,500 if married filing separately). Anything left over carries forward to future years with no expiration. Because short-term gains are taxed at ordinary income rates as high as 37% while long-term gains top out at 20%, a short-term loss is most valuable when it wipes out a short-term gain.
Why the Short-Term Label Matters
The IRS draws a bright line at the one-year mark. Sell an investment you held for one year or less and the loss is short-term; hold it longer than a year and it’s long-term. The clock starts the day after you buy and runs through the day you sell.
The classification changes what your loss is worth. Long-term capital gains get preferential rates of 0%, 15%, or 20% depending on taxable income.1Internal Revenue Service. Topic No. 409, Capital Gains and Losses Short-term gains get no such break. They’re taxed as ordinary income at rates up to 37%. So a short-term loss that cancels a short-term gain saves you more per dollar than a loss offsetting a long-term gain.
How Gains and Losses Are Netted
You can’t just lump every win and loss together. The IRS requires a specific netting sequence: same-type first, cross-type second.
- Short-term losses offset short-term gains. Long-term losses offset long-term gains. After this step you have either a net short-term amount and a net long-term amount, each of which can be a gain or a loss.
- If one category shows a net loss and the other a net gain, the loss offsets the gain. Whatever remains is your overall capital gain or loss for the year.2Internal Revenue Service. 2025 Instructions for Schedule D (Form 1040)
A Worked Example
Say you have $2,000 in short-term gains and $10,000 in short-term losses this year, along with $15,000 in long-term gains and $5,000 in long-term losses. Same-type netting produces a net short-term loss of $8,000 and a net long-term gain of $10,000. Cross-type netting then applies the $8,000 short-term loss against the $10,000 long-term gain, leaving a $2,000 net long-term gain as your taxable result.
Notice what that $8,000 short-term loss actually did: it erased $8,000 of long-term gain that would have been taxed at preferential rates. Had the numbers been reversed and a net long-term loss offset a net short-term gain, the savings per dollar would be larger, because the short-term gain would have faced ordinary rates. Order matters.
The $3,000 Deduction Against Ordinary Income
When losses exceed gains after both rounds of netting, you can deduct the resulting net capital loss against ordinary income such as wages, salary, and interest. The annual cap is $3,000, or $1,500 for married filing separately.1Internal Revenue Service. Topic No. 409, Capital Gains and Losses
The deduction runs dollar for dollar up to that cap. A net capital loss of $1,800 deducts in full at $1,800. A net capital loss of $25,000 still deducts only $3,000 this year, and the remaining $22,000 carries forward.
Relative to a large loss, $3,000 a year is small. An investor sitting on $50,000 of unused capital losses with no future gains to offset would need nearly 17 years to work through it. That’s why harvesting losses across the year to match against gains in the same year usually beats waiting to deduct a single big loss $3,000 at a time.
Capital Loss Carryovers
Any net capital loss above the annual cap rolls to the next tax year. There’s no expiration; the unused loss carries forward until fully absorbed.1Internal Revenue Service. Topic No. 409, Capital Gains and Losses
The carryover keeps its character. A short-term loss carries forward as short-term; a long-term loss carries forward as long-term. In the following year those carried amounts enter the netting process alongside fresh gains and losses.3Office of the Law Revision Counsel. 26 U.S. Code 1212 – Capital Loss Carrybacks and Carryovers A short-term carryover first offsets future short-term gains, which is the most tax-efficient use.
One quirk catches people off guard. In computing next year’s carryover, the $3,000 deduction you claimed is treated as if it were a short-term capital gain, which reduces your short-term carryover before it reduces the long-term carryover. So the carryover figure isn’t simply “net capital loss minus $3,000.” The Capital Loss Carryover Worksheet in the Schedule D instructions walks through the actual math.
Carryovers Expire at Death
Unlike most tax attributes, capital loss carryovers do not transfer to your estate, heirs, or surviving spouse. Under Rev. Rul. 74-175, any unused carryover disappears when the taxpayer dies. The loss can only be used on the final return for the year of death, still subject to the same $3,000 annual limit. If you’re holding a large carryover and are in poor health, realizing capital gains before death can put those losses to work rather than let them vanish.
The Wash Sale Rule
The wash sale rule is the single most common way a planned short-term loss gets disallowed. If you sell a security at a loss and buy the same or a substantially identical security within 30 days before or after the sale, the IRS disallows the loss entirely.4Office of the Law Revision Counsel. 26 U.S. Code 1091 – Loss From Wash Sales of Stock or Securities
The 30-day window runs in both directions. Buy a replacement share on Day 1, then sell the original on Day 15 at a loss: wash sale. Sell at a loss on Day 1, then repurchase on Day 25: also a wash sale. The full restricted window is 61 days.
The loss isn’t usually gone forever. The disallowed amount gets added to the cost basis of the replacement shares, which defers the tax benefit until you sell those shares in a later transaction that isn’t itself a wash sale.4Office of the Law Revision Counsel. 26 U.S. Code 1091 – Loss From Wash Sales of Stock or Securities
Watch Automatic Reinvestments and Other Accounts
Two situations trigger wash sales that investors don’t see coming. Automatic dividend reinvestment can repurchase shares of a fund you just sold at a loss; if that reinvestment falls inside the 30-day window, it disallows part or all of your loss.5Internal Revenue Service. Case Study 1: Wash Sales Turn off automatic reinvestment before executing a tax-loss sale.
The rule also applies across all your accounts, including IRAs, and across your spouse’s accounts. Sell a stock at a loss in your taxable brokerage account and your spouse buys the same stock in an IRA within 30 days, and the loss is disallowed. Worse, because cost basis inside an IRA isn’t tracked the way it is in a taxable account, a wash sale triggered by an IRA purchase can permanently kill the deduction rather than defer it. Brokers only track wash sales within the same account and the same security identifier, so cross-account monitoring is your job.
Losses That Don’t Qualify
Not every drop in value produces a deductible loss.
Losses on personal-use property, including your home, personal vehicle, and household furniture, are not deductible.1Internal Revenue Service. Topic No. 409, Capital Gains and Losses The asset must have been held for investment or used in a trade or business.
Losses on sales to related parties are also disallowed. That includes siblings, your spouse, parents, and children, and it extends to sales between you and a corporation or partnership in which you own more than 50%.6Office of the Law Revision Counsel. 26 U.S. Code 267 – Losses, Expenses, and Interest With Respect to Transactions Between Related Taxpayers You can’t engineer a deductible loss by shifting assets to someone you control.
One more boundary worth flagging: inherited assets are automatically treated as long-term regardless of how briefly you or the decedent held them, so they can’t produce a short-term loss.
How to Report It
Two forms do the work. Form 8949 lists each sale with acquisition date, sale date, proceeds, and cost basis, separated into short-term and long-term sections. Those totals feed Schedule D, which runs the netting calculations and produces your net capital gain or loss.7Internal Revenue Service. Instructions for Form 8949 (2025)
If Schedule D line 16 is a loss, the form limits your deduction to the smaller of your total loss or $3,000 ($1,500 if MFS), and that capped figure moves to Form 1040, line 7.8Internal Revenue Service. 2025 Schedule D (Form 1040) If any loss remains, the Capital Loss Carryover Worksheet in the Schedule D instructions splits it into the short-term and long-term amounts you’ll carry into next year.
Losses Also Reduce the Net Investment Income Tax
High earners pay an additional 3.8% Net Investment Income Tax on capital gains once modified adjusted gross income exceeds $200,000 for single filers or $250,000 for married couples filing jointly.9Internal Revenue Service. Questions and Answers on the Net Investment Income Tax Those thresholds aren’t indexed for inflation, so more filers cross them each year. Capital losses reduce net investment income, which can shrink or eliminate the surtax. For someone hovering near the threshold, a well-timed short-term loss can save the ordinary income tax on the offset gain plus the 3.8% NIIT on top.