If you’re doing U.S. taxes in late February, you may be staring at your tax software (or a preparer’s checklist) and wondering why it suddenly wants you to pick between “FIFO” and “specific identification.” The names sound technical, but they’re really just different ways of describing which purchase you’re treating as sold when you dispose of crypto.
This article is a documentation-first explainer: what the terms generally mean, why your records matter more than the buzzwords, and what to gather before you file. It’s general information, not tax advice, and it’s not telling you which method to use—because the right approach depends on your facts and what you can support with records.
Why your transaction history quality matters more than buzzwords
When you sell, trade, or otherwise dispose of crypto, the big tax question is usually: what was your cost basis for the units you disposed of? Cost basis is generally what you paid (plus or minus certain adjustments) for a particular unit, and it’s used to figure gain or loss.
That’s where “lots” come in. A lot is a chunk of crypto you acquired at a specific time and price—think of it like a receipt for a specific purchase. If you bought the same coin on multiple dates at different prices, you may have multiple lots. When you later dispose of some of that coin, you’re effectively choosing which lot(s) you disposed of.
The catch: no cost basis approach is stronger than the underlying records. In practice, messy histories happen—multiple exchanges, wallet-to-wallet transfers, token migrations, or old accounts that no longer exist. Tax software can only do so much if the inputs are incomplete or inconsistent.
FIFO and specific identification, explained in plain English
FIFO stands for “first in, first out.” Conceptually, it assumes the earliest units you acquired are the first ones you disposed of. People mention FIFO because it’s straightforward to apply when you have a complete timeline of buys and sells for a given asset.
Specific identification is the idea that you can identify exactly which units (which lot) you disposed of—rather than relying on a default ordering assumption. Conceptually, it’s more “receipt-driven”: you’re tying a disposal to particular acquisition details. The key practical point is that specific identification generally depends on having clear, consistent documentation that connects what you sold to what you bought.
Why transfers complicate everything: moving crypto between your own wallets or exchanges typically isn’t a taxable sale by itself, but it can break the paper trail if the transfer isn’t labeled and linked. If an exchange shows an incoming deposit with no purchase history attached, your software might treat it like “unknown basis” unless you provide the missing acquisition details.
The documentation checklist: dates, amounts, fees, and transfers
If you do one thing before you pick settings in software or answer a preparer’s questionnaire, make it this: get your records into a form that can be verified. A strong package usually includes:
- Acquisitions: date/time acquired, asset name/ticker, quantity, price in USD (or your reporting currency), and the platform/wallet where it happened.
- Disposals: date/time disposed, quantity, proceeds in USD, and what you received (cash, another coin, goods/services, etc.).
- Fees: trading fees, network fees, and any platform fees, with dates and which transaction they relate to.
- Transfers: for every wallet/exchange move, keep the date/time, quantity, from/to addresses (or account IDs), and the transaction ID/hash when available.
- Statements and exports: CSV exports from each exchange, plus any year-end summaries. Keep original files—don’t rely only on screenshots.
- Notes for “weird” events: mergers, token swaps, airdrops, staking rewards, or re-denominations—anything that changes what you hold or how it’s labeled.
When people search “Form 8949 crypto basis,” what they’re really running into is the need to report disposals with enough detail to support proceeds, dates, and basis. Clean inputs now can prevent a frustrating scramble later.
Questions to ask a tax professional before you assume anything
If your history is simple, software may be enough. But if you used multiple platforms, have missing data, or are unsure how “lots” are being tracked, it can be worth talking to a qualified tax professional. Bring your exports and ask practical questions like:
- “Given my records, what cost basis approach can I actually substantiate?”
- “If I transfer between wallets, what do you need to link those movements so they don’t become ‘unknown basis’?”
- “How should I handle transactions that show up without complete acquisition details?”
- “What assumptions does my software make, and how do we document them?”
- “What should I keep in my files in case I need to explain my reporting later?”
One gentle reminder: this is educational information, not tax, legal, or financial advice. Crypto tax rules and documentation expectations can be nuanced, so it’s smart to confirm how they apply to your situation.
Sources
Recommended sources to consult (and references for verification). If you want to go deeper, verify current IRS language on basis identification and documentation expectations, and confirm how your situation should be handled with a qualified professional.
- Internal Revenue Service (irs.gov)
- Taxpayer Advocate Service (taxpayeradvocate.irs.gov)
- American Institute of CPAs (aicpa.org)
- SEC Investor.gov (investor.gov)
- National Association of Enrolled Agents (naea.org)