Short answer: a loss only becomes usable once it is realized — that is, when you actually dispose of the asset. A position that has fallen in value while you still hold it produces no deduction, no matter how far it has fallen. Once realized, the capital loss first offsets capital gains; any remaining net loss is deductible against ordinary income up to an annual limit, and the excess carries forward to future years indefinitely.
The practical work is documentary, not arithmetic. Most taxpayers who lose the benefit of a real loss do so because they cannot prove their cost basis, not because the loss was rejected. This guide explains what counts, how it is calculated, what substantiates it — and, importantly, which of the classic crypto tax disasters are not ordinary crypto capital losses.
What counts as a realized loss
The distinction is between a price decline and a completed transaction.
Unrealized (no deduction). You bought at $40,000 and the asset now trades at $15,000. You still hold it. For tax purposes nothing has happened. The paper loss is real economically and invisible for tax.
Realized (reportable). You disposed of the asset. Any of these is a realized loss event:
- Selling for dollars or other fiat currency
- Exchanging one digital asset for another, including a swap into a stablecoin — see crypto-to-crypto swaps
- Spending crypto on goods or services
- Paying a network or protocol fee in crypto (a disposition of the units spent)
What is not a disposition: moving assets between wallets and accounts you control. That is a transfer — see transfers between your own wallets. A transfer never produces a loss, and classifying one as a sale creates a phantom result that will not survive review.
The formula
Proceeds − adjusted cost basis = gain or loss
- Proceeds: what you received, measured in dollars at the time of disposition. In a swap, it is the fair market value of the asset received, not a figure printed on a bank statement.
- Adjusted cost basis: what you paid, including capitalized acquisition costs such as trading fees.
- Fees: acquisition fees increase basis; disposition fees reduce proceeds. Apply each once. Counting a fee on both sides is a common and detectable error.
A negative result is a capital loss. It is computed lot by lot, not across the whole portfolio. Selling part of a position requires identifying which units were sold, using a method applied consistently account by account under the wallet-by-wallet rules now in force.
Worked example
Assumptions: US individual; capital-asset treatment; single account; no wash-sale or constructive-sale issues; figures rounded and illustrative.
Acquisition, February 2025: buys 3 SOL for $600 plus a $9 fee. Adjusted basis: $609.
Disposition, November 2025: sells the 3 SOL for $410 gross. The platform charges an $8 fee.
| Item | Amount |
|---|---|
| Gross proceeds | $410 |
| Less sale fee | ($8) |
| Net proceeds | $402 |
| Less adjusted basis | ($609) |
| Short-term capital loss | ($207) |
The holding period is under one year, so the loss is short-term and offsets short-term gains first. Note that the fees moved the result $17 in the taxpayer’s favor — across hundreds of trades, fee treatment is not a rounding detail.
Documents that substantiate a loss
The burden of proof rests on the taxpayer. For each disposition, gather:
- Acquisition record: purchase confirmation, date, quantity, and cost in USD
- Disposition record: sale or swap confirmation, date, quantity, and proceeds in USD
- Fee documentation: trading, network, and protocol fees
- Complete CSV exports from every platform used that year, including closed accounts
- Transaction hashes and wallet addresses for on-chain activity
- USD valuation source and method, where the platform reported no dollar figure
- Broker forms: 1099-DA, 1099-B, and any corrected versions
- Prior-year returns establishing carried-over basis and loss carryforwards
If the basis is what is missing, that is the problem to solve first — see Form 1099-DA missing cost basis. A loss you cannot substantiate is a loss you cannot defend.
How losses interact with gains
Capital results offset in a defined order. The sequence matters because short-term gains are taxed at ordinary rates, so where the loss applies changes the outcome. This is the core of how to report crypto losses.
- Short-term losses offset short-term gains; long-term losses offset long-term gains.
- The net loss remaining in one category offsets the net gain in the other.
- The resulting net capital loss is deductible against ordinary income, subject to an annual limit: $3,000 for most individuals and $1,500 for married filing separately. This is the crypto loss tax deduction in practice.
- Anything exceeding the annual limit carries forward to future years.
Capital losses generally offset capital gains and only a limited amount of ordinary income; they do not offset wages without limit. Confirm the limit for your year and filing status in IRS materials before relying on any figure — these thresholds are set by statute and can change.
Report dispositions on Form 8949, carry totals to Schedule D, and from there to Form 1040. Losses must be reported to be used. An unreported loss is forfeited value, and the same records that substantiate a loss are what later answer an IRS CP2000 notice.
Loss carryforward
An unused net capital loss moves to the next year and, if still unused, continues to carry forward indefinitely for individuals. The loss carryforward keeps its character: a long-term loss carries forward as a long-term loss.
Two practical points. First, the carryforward is tracked, not automatic; you must report it each year to preserve it, and a skipped year is a year of documentation you will have to rebuild. Second, the deduction against ordinary income applies year by year, so a large loss may take many years to absorb. Keep the schedule with your permanent records, not just with the loss year’s file.
Whether a particular carryforward produces a benefit depends on your future gains and income. No general guide can promise a specific outcome.
What is not an ordinary capital loss
This is where crypto departs sharply from intuition, and where much of the advice circulating online is simply wrong. Each of the following raises its own questions and none should be treated as an automatic deduction.
Price decline without a sale. Without a disposition there is no deduction. Riding out a decline produces nothing reportable.
Lost keys or inaccessible wallet. You still own the asset; you simply cannot reach it. There is no disposition, and casualty or theft deductions for personal property are tightly restricted for individuals under current rules.
Funds stolen or taken in a hack. Theft-loss treatment is limited for individuals under current law, and the analysis differs depending on whether the loss arose in a transaction entered into for profit. Do not assume a deduction exists.
Platform collapse or bankruptcy. While the insolvency proceeding remains open, the ultimately recoverable amount is unknown, which generally prevents fixing the loss. The claim may retain value; recovery may arrive years later and for a fraction.
Investment frauds and scams. Some scam losses are analyzed under a different framework from ordinary capital losses, with materially different rules and documentation requirements. The characterization matters more than the word the victim uses.
Tokens sent to a wrong or unrecoverable address. Whether an abandonment or worthlessness position can be sustained depends on the specific facts and evidence about the asset’s state.
Worthless or delisted tokens. Proving worthlessness is an evidentiary matter, and a token still trading at a fraction of a cent is not worthless.
Each of these deserves its own analysis and, where amounts are material, professional advice. Reporting any of them as a simple capital loss because it looks like a loss is the fastest way to make a position indefensible.
Short-term vs. long-term
The holding period runs from the day after acquisition through the day of disposition.
- One year or less: short-term. Offsets short-term gains, which are taxed at ordinary rates.
- More than one year: long-term. Offsets long-term gains, which are taxed at preferential rates.
For losses, the practical consequence is which bucket the loss enters first. A short-term loss offsetting a short-term gain shelters income taxed at a higher rate than a long-term loss offsetting a long-term gain.
Remember that a swap restarts the clock: the asset received begins a new holding period on the trade date.
Crypto tax software errors
Automated crypto tax tools reconstruct history from exports and on-chain data, and their failures distort losses systematically.
- Presumed zero basis. Assets transferred from another platform arrive with no acquisition history and the tool silently records basis as zero, turning a real loss into a phantom gain.
- Missing purchase leg. An acquisition that never imported leaves a disposition with nothing to offset against.
- Duplicated trades. An API import run twice, or a CSV merged over the same period, records the same disposition repeatedly.
- Incomplete wallet coverage. A single unconnected wallet breaks the chain of custody for every lot that passed through it.
- Transfers read as sales. Transfers between your own accounts recorded as dispositions create phantom gains and losses alike.
- Fee double-counting. Deducted in the ledger and again in the basis calculation.
- Time-zone drift. Exports in different zones push dispositions across the year-end boundary and put a loss in the wrong year.
Reconcile totals against each platform’s annual statement and hand-check your largest dispositions. A loss produced by a tool you have not tested is a loss you will not be able to explain.
FAQ
Can crypto losses offset stock gains?
Capital losses offset capital gains generally, without regard to the asset class that produced them. The holding-period ordering still applies.
Is a loss on a swap into a stablecoin deductible?
Yes, if realized. Swapping a depreciated token for USDC is a disposition and produces a capital loss on the token disposed of.
What about NFT losses?
An NFT disposed of at a loss generally produces a capital loss, though certain collectibles considerations can affect gain treatment. The hardest issues are usually substantiation and valuation.
The platform shut down and I can’t export my history. What now?
Rebuild from bank and card statements, on-chain records, email confirmations, and prior returns. Where a figure is genuinely unrecoverable, use a defensible contemporaneous source and document the methodology and its limits in writing.
Do wash-sale rules apply to crypto?
The statutory wash-sale rule is written in terms of stocks and securities. Its application to digital assets has been the subject of repeated legislative proposals, so verify the current state for your filing year rather than relying on old commentary.
I never received a Form 1099. Can I still claim the loss?
Yes. The obligation to report — and the right to claim a loss — does not depend on receiving a broker form. DeFi and some foreign platforms issue none.
Should I sell at a loss just to reduce taxes?
That is an investment decision with tax consequences, not a tax decision. Weigh your position as a whole and, where amounts are material, with advice.
Primary sources
- IRS, Topic no. 409, Capital gains and losses
- IRS Publication 544, Sales and Other Dispositions of Assets
- IRS Publication 551, Basis of Assets
- Instructions for Form 8949 and Schedule D for the applicable tax year
Verify the limits and rules current for your filing year before relying on any figure in this guide.
This guide is general information, not tax advice, and does not address any specific taxpayer’s circumstances.
Need help organizing the records behind a reported loss? Contact HolderTax for crypto tax help.
