How to Use Your 1099-DA to Fill Out Form 8949

Your Form 1099-DA has arrived from your crypto exchange. Now what? This guide walks you through exactly how to use that form to complete IRS Form 8949 and report your cryptocurrency gains and losses.

What You'll Need

Before you start, gather:

• Your 1099-DA form(s) from each exchange
• Your own transaction records (for cost basis—more on this below)
• Blank Form 8949 (download from IRS.gov)
• Schedule D (Form 1040)

Quick Overview: What Each Form Does

1099-DA: Reports your crypto sales proceeds to you and the IRS. Shows what you sold and for how much.

Form 8949: Where you report each sale, including your cost basis and calculated gain or loss. This is what you file with your tax return.

Schedule D: Summarizes your total capital gains and losses from Form 8949.

The Critical Issue: Missing Cost Basis

Here's the problem: For the 2025 tax year, your 1099-DA likely shows blank or $0 cost basis. Brokers aren't required to report cost basis until reporting for the 2026 tax year.

This means your 1099-DA shows the IRS what you sold, but not what you paid. If you file without adding your cost basis, you'll pay taxes on the full sale amount—not just your actual profit.

You must calculate and report your own cost basis on Form 8949.

Step-by-Step: Transferring 1099-DA to Form 8949

Step 1: Choose the Right Form 8949 Section

Form 8949 has two parts:

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

Each part has checkbox options based on whether your 1099-DA reported cost basis to the IRS.

For 2025 1099-DAs, you'll likely check Box B or C.

Short Term:

• G – On the DA with cost basis reported to IRS
• H – On the DA without cost basis reported to IRS
• I – Not on the DA

Long Term:

• J – On the DA with cost basis reported to IRS
• K – On the DA without cost basis reported to IRS
• L – Not on the DA

Step 2: Fill Out Column (a) – Description

Enter a description of the asset you sold. Keep it simple—asset name and quantity.

Example entries:

• BTC (0.5)
• ETH (2.0)
• USDC (1,000)

Step 3: Fill Out Column (b) – Date Acquired

Enter the date you originally purchased or received the asset.

This information is NOT on your 1099-DA. You need to look up when you bought the crypto using your exchange's transaction history, your own records, or crypto tax software like Summ.

The acquisition date determines whether your gain is short-term or long-term.

Step 4: Fill Out Column (c) – Date Sold

Enter the date you sold the asset. This is on your 1099-DA.

Step 5: Fill Out Column (d) – Proceeds

Enter the sale amount from your 1099-DA. This is the gross proceeds—how much you received from the sale.

Important: This number must match what's on your 1099-DA. The IRS will cross-reference.

Step 6: Fill Out Column (e) – Cost Basis

This is the critical column. Enter what you originally paid for the asset, including any purchase fees.

Your 1099-DA probably shows this as blank or $0. You must fill in the accurate amount.

If you bought 1 ETH for $2,000 and paid a $10 fee, your cost basis is $2,010.

Step 7: Fill Out Column (f) – Adjustment Code

For 2025 transactions, you can skip this column entirely. Exchanges are not required to report cost basis to the IRS on 1099-DA this year, so there's no basis on record for the IRS to compare yours against. The adjustment code column is only relevant for tax years 2026 and beyond.

One thing worth knowing: your copy of the 1099-DA from the exchange may show cost basis, but that information wasn't sent to the IRS. You're not correcting a discrepancy when you report your own basis. You're simply providing information the IRS doesn't have.

Leave this column blank for 2025.

Step 8: Fill Out Column (g) – Adjustment Amount

Since you're leaving column (f) blank for 2025, leave this one blank too.

Step 9: Fill Out Column (h) – Gain or Loss

Calculate: Proceeds (d) – Cost Basis (e) = Gain or Loss

• Positive number = Capital gain (you owe taxes)
• Negative number = Capital loss (write it in parentheses)

Example:

• Proceeds: $3,500
• Cost Basis: $2,000
• Gain: $1,500

Complete Example

Let's say your 1099-DA shows a Bitcoin sale on 06/15/2025 with $45,000 in proceeds and $0 (blank) cost basis. You know from your records that you bought this Bitcoin on 03/01/2024 for $28,000.

Your Form 8949 entry (Part II, Long-Term, Box K):

• (a) Description: 1.0 Bitcoin
• (b) Date Acquired: 03/01/2024
• (c) Date Sold: 06/15/2025
• (d) Proceeds: $45,000
• (e) Cost Basis: $28,000
• (f) Adjustment Code: —
• (g) Adjustment: —
• (h) Gain or Loss: $17,000

This goes in Part II because you held for more than one year (long-term).

What If You Have Multiple Transactions?

If you have many transactions, you have two options.

Option 1: List Each Transaction. Enter every sale on Form 8949, one per row.

Option 2: Use a Summary Statement. If you have too many transactions to list individually, check the appropriate box (G, H, I, J, K, or L), enter "See attached statement" in column (a), enter totals in columns (d), (e), and (h), and attach a detailed statement listing each transaction. Crypto tax software generates this statement automatically.

Transferring to Schedule D

After completing Form 8949:

1. Add up all short-term gains/losses from Part I
2. Add up all long-term gains/losses from Part II
3. Transfer short-term totals to Schedule D, Part I
4. Transfer long-term totals to Schedule D, Part II

Schedule D calculates your net capital gain or loss, which flows to your Form 1040.

Common Mistakes to Avoid

1. Using the 1099-DA cost basis as-is. If it shows $0 or blank, you'll massively overpay. Always calculate your actual cost basis.

2. Wrong holding period. Double-check your acquisition dates. Short-term gains are taxed at ordinary income rates (up to 37%). Long-term gains get preferential rates (0%, 15%, or 20%).

3. Mismatched proceeds. Your proceeds on Form 8949 must match your 1099-DA. The IRS receives a copy and will flag discrepancies.

4. Forgetting multiple exchanges. If you received 1099-DAs from Coinbase, Kraken, and Gemini, you need to report transactions from all three.

5. Ignoring transferred assets. If you transferred crypto from one exchange to another before selling, the selling exchange doesn't know your cost basis. You must track it yourself.

How Summ Makes This Easy

Manually transferring dozens (or thousands) of transactions from 1099-DAs to Form 8949 is tedious and error-prone. Summ automates the entire process:

• Imports all your transactions from 3,500+ exchanges and wallets
• Tracks cost basis across platforms—even for transferred assets
• Generates pre-filled Form 8949 with accurate cost basis
• Reconciles with your 1099-DA to clarify where transactions match, and resolve where they do not
• Exports to TurboTax and H&R Block for seamless filing

Instead of hours of manual data entry, you get IRS-compliant forms in minutes.

Generate Your Form 8949

Summary Checklist

• Collect all 1099-DAs from every exchange
• Determine acquisition dates for each asset (from your records)
• Calculate cost basis for each sale
• Choose correct Form 8949 part (short-term vs. long-term)
• Check Box H or K if cost basis wasn't reported to IRS
• Ensure total proceeds in Checkbox H and K sum to total proceeds across all 1099-DAs
• Enter your calculated cost basis
• Calculate gain or loss for each transaction
• Transfer totals to Schedule D
• Keep documentation for at least 3 years

This guide is for informational purposes only and does not constitute tax advice. Consult a qualified tax professional for advice specific to your situation.