FIFO, LIFO, HIFO: The Accounting Method Choice That Changes Your Tax Bill
Which lot counts as "sold" when you have crypto bought at different prices and times — and why picking the wrong accounting method can mean paying tax on a gain when you actually realized a loss.
Say you bought the same asset three times: once at $60,000, once at $40,000, and once at $20,000. Today it’s trading at $30,000, and you want to sell one unit. Depending on which purchase you treat as the one you’re selling, that single sale is either a $30,000 loss, a $10,000 loss, or a $10,000 gain. Same asset, same sale, same price — three completely different tax outcomes, decided entirely by an accounting rule most people never actively choose.
That rule is your cost-basis method, and it’s one of the least explained parts of crypto tax reporting. Tax-Loss Harvesting for Crypto covers why realizing a loss deliberately can offset gains — but it assumes you already know which lot you’re realizing. This is the piece that fills that gap.
This is general educational information, not tax advice. Which methods are permitted, and under what conditions, varies by jurisdiction and can change over time. Confirm the current rules where you file before relying on any of this.
What a “lot” actually is
Every time you acquire an asset — buying it, receiving it as a reward, swapping into it — you create a lot: a specific quantity, acquired on a specific date, at a specific cost basis. If you’ve bought the same asset five separate times, you hold five lots, even though your exchange or wallet interface usually just shows you one combined balance.
The combined balance is the problem. When you go to sell a portion of that balance, something has to decide which lot (or lots) you’re actually disposing of, because different lots almost always have different cost bases. That “something” is your accounting method.
The main methods, in plain terms
FIFO (First-In, First-Out). You’re treated as selling your oldest lots first. This is the most common default method, and often the one applied automatically if you haven’t specified otherwise. In a market that’s trended upward over a long holding period, FIFO tends to realize your largest gains first, since your oldest lots usually have the lowest cost basis.
LIFO (Last-In, First-Out). You’re treated as selling your most recently acquired lots first. In a rising market, this can reduce realized gains in the short term, since your newest lots have a cost basis closer to the current price. Not every jurisdiction permits LIFO for this asset class — confirm before assuming it’s available to you.
HIFO (Highest-In, First-Out). You’re treated as selling whichever lot has the highest cost basis, regardless of when it was acquired. This method is specifically aimed at minimizing realized gains (or maximizing realized losses) in the current transaction, since you’re always disposing of the most expensive lot first. Where it’s permitted, it’s the method most directly useful for tax-loss harvesting.
Specific identification. Rather than a fixed rule, you choose exactly which lot you’re selling at the time of the transaction, provided you can document which one it was. This gives you the most control — effectively letting you choose FIFO, LIFO, HIFO, or any other selection on a trade-by-trade basis — but it usually comes with stricter recordkeeping requirements to prove which lot you actually sold, not just which lot would have been most convenient in hindsight.
Working the example all the way through
Back to the $60,000 / $40,000 / $20,000 lots, selling one unit at $30,000:
- FIFO disposes of the $60,000 lot first → a $30,000 realized loss.
- LIFO disposes of the $20,000 lot first → a $10,000 realized gain.
- HIFO disposes of the $60,000 lot first (it’s also the highest-cost lot here) → the same $30,000 realized loss as FIFO in this particular case.
- Specific identification lets you choose any of the three outcomes above, depending on what you actually want to report this year.
Notice that FIFO and HIFO happen to agree in this example only because the oldest lot also happens to be the most expensive one. That won’t always be true — if your oldest lot had actually been the $20,000 purchase and your $60,000 purchase came later, FIFO and HIFO would diverge sharply. This is exactly why the method matters independently of just knowing your purchase history: the same set of lots, the same sale, produces different numbers depending on which rule sorts them.
Why this matters more for crypto than for stocks
A traditional brokerage account usually tracks cost basis for you automatically and reports it to both you and the tax authority, often defaulting to one method unless you actively elect another through the platform. Crypto rarely works this way. If your activity spans multiple exchanges, self-custody wallets, or chains, no single platform has visibility into your full lot history — which means the responsibility for applying a method consistently, and having the records to back it up, falls on you. The Records You Actually Need to Claim a Capital Loss covers the underlying recordkeeping this depends on; without it, none of the methods above are usable in practice, because you can’t sort lots you can’t document.
The mistake this section exists to prevent
The costly version of this mistake isn’t picking the “wrong” method in some abstract sense — it’s not picking one deliberately at all, and having your exchange, wallet software, or tax software apply a default you never evaluated. In a year where you’re trying to realize losses to offset gains, a default that happens to sell your lowest-cost-basis lots first can turn a year you meant to use for loss harvesting into one where you accidentally book a gain instead. Before executing a loss-harvesting sale, check which method your records (or your tax software) are actually using — don’t assume.
A practical starting checklist
- Identify which cost-basis method your tax software, exchange export, or accountant is currently applying by default.
- Before a deliberate loss-harvesting sale, confirm which specific lot that method will select — don’t assume it’s the one with the outcome you want.
- If your jurisdiction permits specific identification and you want more control, confirm what documentation is required to support it, and keep that documentation at the time of the trade, not reconstructed afterward.
- If you’ve never actively chosen a method, treat that as an open question worth resolving with a tax professional before your next significant sale, not after.
FAQ
Can I switch accounting methods every year, or even every trade? Rules vary by jurisdiction — some require consistency once you’ve adopted a method, others allow more flexibility, and some only permit specific identification if you can document it at the time of each sale, not retroactively. Check your specific jurisdiction’s current rule before assuming you can switch freely.
What happens if I don’t pick a method at all? Most tax authorities default to a specific method (commonly FIFO) if you haven’t documented another approach, or if your records aren’t detailed enough to support specific identification. Not choosing is itself a choice — usually the one that’s easiest to enforce, not the one that’s best for you.
Does the accounting method change how much tax I ultimately owe over the life of a position? Not necessarily — if you eventually sell your entire position, the total gain or loss across all lots is the same regardless of method. What the method changes is timing: which gains or losses land in which tax year, which can matter a great deal for that year’s bill even though the lifetime total is unaffected.