Extended Your 2025 Return? How to Report Crypto Sales by October 15

If you extended your 2025 federal return, you have until October 15 to file—including a report of your digital-asset sales. An extension gives you six more months to submit your return, but any tax owed was still due by April 15. Here's how to gather your records, calculate gains, and complete Form 8949 in time.

Why the October 15 Deadline Matters for Crypto

Most taxpayers face an April 15 filing deadline. If you filed Form 4868 by April 15, 2026, the IRS granted an automatic six-month extension, moving your deadline to October 15. That extension covers everything on your return—including the capital gains and losses from digital-asset sales you made in 2025.

Many crypto traders miss this deadline because they don't have their records organized. You'll need your transaction history from every exchange and wallet you used—purchases, sales, deposits, and withdrawals—to calculate basis and recognize gain or loss. Waiting until late September to gather those records leaves you scrambling during the busiest filing period.

Step 1: Gather Your Transaction History from Every Source

Start by listing every platform where you held crypto in 2025:

• Coinbase, Kraken, Crypto.com, Gemini, Robinhood (or other custodial exchanges)
• Self-custody wallets (hardware wallet, MetaMask, Ledger, etc.)
• DeFi platforms, staking services, or mining pools (if you earned crypto)
• Peer-to-peer sales or trades

For each custodial exchange, log in and navigate to the tax or statements area. Exchanges typically have a "Tax Documents," "Statements," or "Reports" section. Download the full transaction history for 2025 as a CSV file. This export should include the date, asset, quantity, price in USD at the time, and transaction type (buy, sell, deposit, withdrawal, earn, fee).

For self-custody, you'll need to track acquisitions and sales manually or use a transaction import tool. Record when you bought or received the asset (with the cost in U.S. dollars) and when you sold it. Self-custody is often overlooked—but a sale from your MetaMask wallet counts as a capital event, even if the exchange never filed a Form 1099 on your behalf.

Step 2: Identify Which Sales Require Reporting

You report capital gains and losses on Form 8949 and Schedule D. A sale occurs when you:

• Exchange crypto for U.S. dollars on an exchange
• Trade one digital asset for another (e.g., Ethereum for Bitcoin)
• Spend crypto to buy a good or service
• Sell crypto from a self-custody wallet to anyone

Receiving crypto as income (staking rewards, mining, airdrops, or wages paid in crypto) is taxable as ordinary income at the time you receive it, not a capital gain. But when you later sell that crypto, you calculate gain or loss from your basis (the value when you received it) to your sale price.

Transfers between your own wallets or between your own accounts on the same exchange are not sales and don't trigger tax. Deposits and withdrawals themselves don't create a tax event—only sales do.

Step 3: Assign a Cost Basis to Each Sale

Cost basis is what you paid for the asset, in U.S. dollars. The basis of a digital asset is generally its cost in U.S. dollars. You choose your own method for matching purchases to sales, as long as you use it consistently. The most common methods are:

For most traders, FIFO is easiest because it matches your natural assumption: you sold the first batch you bought. But if you bought Bitcoin in November 2024 at a much higher price than May 2025, selling the old Bitcoin (FIFO) creates a loss, while selling the new Bitcoin creates a gain. Your choice of method can swing your tax outcome significantly.

Document your method before you file. If you later file an amended return, the IRS will want to see that you applied the same method consistently throughout the year.

Step 4: Calculate Short-Term and Long-Term Gains

Assets held more than one year are long-term; one year or less are short-term. Long-term gains use lower tax rates; short-term gains are taxed as ordinary income.

For each sale, count the days from when you acquired the asset to the date you sold it. If the holding period is exactly one year, it is short-term. One year and one day is long-term.

Your Form 8949 will split sales into short-term (Part I) and long-term (Part II). Totals from each part feed into Schedule D, which combines all your capital gains and losses for the year and calculates your net long-term and net short-term gain or loss.

Step 5: Account for Losses

If your capital losses exceed capital gains, you can deduct up to $3,000 of the excess against other income in 2025 ($1,500 if married filing separately). Any excess loss carries forward to 2026.

Whether the wash-sale rule applies to digital assets, and how, is a question to confirm with a tax professional; tax rules for digital assets can change.

Step 6: Handle Missing or Incomplete Records

If an exchange shut down, deleted records, or you can't find documentation for a trade, don't leave the line blank on Form 8949. Reconstruction is allowed. Do your best to find the information:

• Check emails from the exchange confirming the trade.
• Review your bank or credit-card statements for the date and amount of deposits or withdrawals.
• Use public blockchain explorers (e.g., Etherscan for Ethereum) to find on-chain records of dates and amounts if you moved assets to self-custody.
• If you have a reasonable estimate but not an exact price, note it and explain your methodology if the IRS asks.

Reconstructed cost basis is better than omitting the sale. The IRS can propose an adjustment if it receives different information from a broker, but a record you prepared in good faith—especially one based on available evidence—is more defensible than no record at all.

Step 7: Complete Form 8949 and Schedule D

Form 8949 reconciles amounts reported to you and the IRS by brokers with what you report. Starting with transactions on or after January 1, 2025, brokers began issuing Form 1099-DA for digital-asset sales. If you received one, the IRS already has that data and will match it against your return.

Enter each sale (or a summarized line for many sales of the same asset) on Form 8949. Use Column (a) for the description (e.g., "100 Bitcoin"), Column (b) for the date acquired, Column (c) for the date sold, Column (d) for proceeds, Column (e) for basis, and Column (f) for gain or loss.

Subtotals from each part of Form 8949 roll into Schedule D, which nets long-term and short-term gains and losses. The result flows to your Form 1040.

FAQ: October 15 Crypto Filing Questions

Do I Really Have Until October 15, or Is That the Last Day to Pay?

October 15 is your deadline to file the return itself. However, any tax owed was still due on April 15. If you owed tax and did not pay by April 15, interest and penalties can apply, even if you file by October 15. Extensions give you time to prepare your return and gather records, not to delay payment.

I Received a Form 1099-DA, but My Records Don't Match. What Do I Do?

A Form 1099-DA can differ from your own records. Compare the amounts on the form to your own records. If you have evidence (exchange statements, bank records, or blockchain records) showing your sale price was different, record your corrected amount on Form 8949 and file your return with that figure. If the IRS later receives different information from the broker or detects a mismatch, you'll receive a CP2000 notice, which proposes changes based on third-party data and explains how to respond. At that point, you can submit your records to support your position.

I Have Hundreds of Trades. Can I Summarize Them on Form 8949?

Yes. If you have many trades of the same asset in the same holding-period category (all short-term Bitcoin sales, for example), you can group them into one line with a total of proceeds, basis, and gain or loss. However, keep your detailed records for your files in case of an audit; don't attach them to your return unless the IRS specifically asks.

What If I Don't File by October 15?

File as soon as you can. Interest and penalties can apply to tax that was not paid on time; the IRS explains how they work on its extension page. A tax professional can tell you what applies to your return.

Bringing It Together

Reporting crypto sales by October 15 is manageable if you take it step by step. Gather your records from every source, clearly identify your cost-basis method, separate short-term from long-term sales, and fill in Form 8949 with honest, reconstructed figures where needed. Keep your exchange statements and calculations in a folder for your records.

If you have many trades, record-keeping software can save hours of manual work. Hodl1099 offers a free tier for up to 15 transactions per tax year to import your CSVs from Coinbase, Kraken, Crypto.com, Gemini, or Robinhood, assign your basis method, and generate a Form 8949-style report. Paid plans range from $19.99 to $99 depending on your volume. The software handles the calculation side so you can focus on gathering records and meeting your deadline.

October 15 is within reach. Start gathering your records today.