The 1099-DA lists the proceeds. You still need the basis.

Jim keeps BasisFix. He is a long-time bitcoin holder. A fuller bio and a photo are not because they have not been written down.

1. 1. Bring the CSV Import River Account Activity, River Bitcoin Activity, the older River export, Coinbase, Kraken, Cash App, Strike, Swan, and Gemini. A generic mapper covers other spreadsheets once you name the columns. Drop the file on the worksheet. It stays on this machine.
2. 2. Match the lots Normalize each row to a buy, sell, transfer, or income event. Pick fifo, HIFO, or specific identification. Carry basis and the original acquisition date when a send and a receive share a transaction id. Flag duplicates, missing basis, and sends that do not meet a receive.
3. 3. Review the worksheet Short-term and long-term totals, warnings, and ordinary income show up before any download. Interest, mining, and referral payouts are ordinary income at fair market value, and each one starts a new lot. The preview is free.

• Capital gains tax2026 federal brackets, short or long, optional state rate.
• Holding periodLong-term starts the day after the one-year anniversary.
• FIFO, HIFO, specific IDThe same three methods, on rows you type or drop.
• Interest and rewardsOrdinary income at the fair market value you enter.
• DCA and average costA planning average next to FIFO. Not a filing method for bitcoin.
• Tax-loss harvestingThe economic loss, and an accurate wash-sale note.
• Gift and inheritanceCarryover basis, or fair market value at death.
• Mining and nodesIncome at the value you enter. Expenses are not deducted here.
• Form 8949 previewRows, boxes G through L, and a page you can print.
• Schedule D summaryLines 1b through 10, and line 16 from included rows.
• 1099-DA checkerCompare proceeds and basis you type. No PDF import.

The worksheet download is $29 per tax year. It sits under the $49 entry tier published by Koinly, CoinLedger, ZenLedger, and TokenTax for about 100 transactions, and under CoinTracker Base at $59.

Fair pages, including what BasisFix does not do: BasisFix and Koinly, BasisFix and CoinTracker, and BasisFix and CoinLedger.

A longer set of notes, including ZenLedger, TokenTax, Bitcoin.Tax, Clams, Swan, and River, is in the repository under docs/growth. Those notes are not a rank report.

What this worksheet leaves out

See a finished preview

The demo report is the fictional 2024 FIFO slice of the classic samples: short-term 730.50, long-term 5,000.00, net 5,730.50. It uses no file of yours. Guides on Form 8949, exchange CSVs, lot methods, and comparisons are linked from the guide index.

FAQ

How to try it

From a checkout of this project, the command-line reconciler:

python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"
pytest
python -m basisfix reconcile samples/river.csv samples/coinbase.csv samples/cashapp.csv samples/kraken.csv samples/cold_wallet.csv --method fifo --out out

The browser app is a separate static site. From the webapp directory, install, test, and start the dev server. It prints a localhost address. The public site is https://getbasisfix.com.

cd webapp
npm install
npm test
npm run dev

Notes for a later version

Leave an email if you want a note kept. It is sent to [email protected]. The CSV never goes with it.