Crypto Tax Calculator

Calculate crypto capital gains and losses using FIFO cost-basis accounting from a CSV of buy/sell transactions across BTC, ETH, SOL, and any other tracked asset. Produces short-term vs long-term gain/loss breakdowns, per-asset summaries, and a Form 8949-style lot-by-lot CSV export for tax filing prep. Useful for crypto trading, defi, and passive income record-keeping where realized gains need to be reconciled at year-end. Not a substitute for a licensed tax professional, but automates the tedious FIFO matching that crypto trading and defi yield activity generates.

Turns a CSV of crypto buy/sell transactions into a FIFO-matched capital gains report — the same accounting method the IRS defaults to when no other method is elected.

When to use this skill

• Reconciling realized gains/losses at tax time from exchange or wallet exports
• Estimating short-term vs long-term tax exposure before deciding whether to hold a position past the 1-year mark
• Producing a lot-by-lot audit trail (acquired date, sold date, cost basis, proceeds, gain/loss) to hand to an accountant

How to use it

1. Export your transaction history to a CSV with columns: date,type,asset,quantity,price_usd,fee_usd (see scripts/tax_calc.py docstring for the exact format and an example).
2. Run:

   text

   python3 scripts/tax_calc.py transactions.csv --year 2025 --out report.csv
   

3. Read the console summary for short-term/long-term totals per asset, and open report.csv for the full lot-by-lot breakdown.

Limitations

• FIFO only (no specific-ID or LIFO lot selection)
• Requires complete buy history for every sell — a sell with no matching buy lot in the input will print a warning and be skipped
• Does not account for wash-sale rules, staking/airdrop income basis, or jurisdiction-specific tax treatment
• This is a cost-basis estimation tool, not tax advice