Form 8949 in one sentence
Form 8949 is the IRS form where you report every sale, swap, or disposition of a capital asset, including crypto.
What goes on it?
Each row on Form 8949 represents one sale. You fill in:
(a) Description: The asset you sold (e.g., "2.5 ETH")
(b) Date acquired: When you originally bought it
(c) Date sold: When you sold or swapped it
(d) Proceeds: What you received (in USD)
(e) Cost basis: What you originally paid (in USD)
(f) Adjustment code: If the basis needs correcting (e.g., Code B for incorrect basis on a 1099)
(g) Adjustment amount: The dollar amount of the correction
(h) Gain or loss: Proceeds minus cost basis, plus any adjustment
Part I vs Part II
Form 8949 has two parts:
Part I: Short-term gains and losses (assets held 1 year or less)
Part II: Long-term gains and losses (assets held more than 1 year)
Long-term gains are taxed at lower rates (0%, 15%, or 20% depending on income), so the distinction matters.
The checkbox at the top
Each part has three checkboxes (A, B, C):
Box A: Basis was reported to the IRS (you got a 1099-B or 1099-DA with basis)
Box B: Basis was NOT reported to the IRS
Box C: You didn't get a 1099 at all
For most crypto in 2025, you'll check Box C (no 1099-DA yet) or Box B. Starting in 2027 when 1099-DAs arrive, Box A becomes more common, and you'll use the adjustment columns when the 1099-DA disagrees with your records.
What if I have hundreds of sales?
You don't have to list every single sale on the form. The IRS allows you to attach a detailed statement and enter summary totals on 8949. Crypto tax software generates the full statement and the summary for you.
How CryptoTaxPilot handles this
CryptoTaxPilot generates a complete Form 8949 PDF with every sale listed, properly split between Part I (short-term) and Part II (long-term). It also generates a CSV you can import directly into TurboTax or H&R Block.