How to Fill Out IRS Form 8949 for Cryptocurrency Transactions

Form 8949 is the IRS's required report for every individual cryptocurrency sale or exchange. It's not optional — if you sold, traded, or otherwise disposed of any crypto during the year, this form is how you tell the IRS about it in detail. Here's exactly how to complete it correctly.

What Is Form 8949?

Form 8949 (Sales and Other Dispositions of Capital Assets) is where you list every cryptocurrency transaction individually. Each row on the form represents one taxable event — one sale, one trade, one use of crypto to buy something.

The form totals flow to Schedule D, which flows to your Form 1040. The full chain:

The form has two parts:

• Part I — Short-term transactions (held 1 year or less)
• Part II — Long-term transactions (held more than 1 year)

Within each part, there are three possible checkboxes based on how the broker reported the transaction:

• Box A/D — Reported to IRS with basis (broker has full info)
• Box B/E — Reported to IRS without basis (broker reported proceeds but not basis)
• Box C/F — Not reported to IRS (no 1099, or reporting directly to IRS yourself)

For most crypto transactions where you received a 1099-B, use Box B or E (reported but basis may be incomplete). For transactions not on a 1099, use Box C or F.

Filling Out Each Column

Real Example: Filling Out a Row

Scenario: You bought 1 BTC on March 5, 2024 for $42,000 (including $50 in fees). You sold it on January 10, 2025 for $65,000 (with a $75 selling fee).

Holding period: Acquired March 5, 2024 → Sold January 10, 2025 = 10 months and 5 days.Less than one year → Short-term → Part I of Form 8949.

Adjustment Codes Explained

Column (f) uses letter codes to explain why your reported numbers differ from what's on your 1099. Common codes for crypto:

• B — Basis reported incorrectly by broker. Use this when you're correcting the basis on a 1099 (e.g., because you transferred crypto in from another exchange with a different cost basis)
• W — Wash sale not allowed — not applicable to crypto currently
• E — Timing differences between Form 1099-B and your records

When you use an adjustment code, put the adjusted amount in column (g) and explain it. The IRS may follow up if there are large unexplained discrepancies between your 8949 and 1099s on file.

Handling Hundreds (or Thousands) of Transactions

If you're an active trader with thousands of transactions, entering each one individually is impractical. The IRS allows you to:

1. Summarize by broker and short/long-term category on a single 8949 row
2. Attach a statement with the full transaction details
3. Use software-generated 8949 forms that include all individual transactions

The summary approach is allowed when the totals match your 1099 exactly. If you have adjustments (different basis, corrections), you usually need to show the individual transactions with adjustments separately.

Conclusion

Form 8949 is the backbone of crypto tax reporting — every taxable event gets its own row, divided by whether it's short or long-term, with gains and losses calculated individually. The form feeds Schedule D, which determines your total capital gains tax.

For anyone with more than a handful of trades, the math gets complex fast. Getting the basis right, applying the correct holding period, and reconciling with any 1099s you received are the main challenges. Tax software handles all of this automatically if you keep good records throughout the year.

This article is for informational purposes only. Consult a tax professional for advice on your specific tax situation.