Cost Basis Method
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Key Takeaway
An accounting rule that determines which specific cryptocurrency units are considered sold during a disposal, establishing the cost basis used to calculate the resulting taxable capital gain or loss.
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What Is Cost Basis Method?
An accounting rule that determines which specific cryptocurrency units are considered sold during a disposal, establishing the cost basis used to calculate the resulting taxable capital gain or loss.
How Cost Basis Method Works
Frequently Asked Questions
What is a cost basis method and which one should I use for cryptocurrency?
A cost basis method is the accounting rule that determines which specific lots of cryptocurrency are treated as sold during a disposal, establishing the cost used to calculate your taxable gain or loss. The three primary methods are FIFO, LIFO, and HIFO. FIFO uses the oldest lots first, LIFO uses the most recent, and HIFO uses the highest-cost lots first. The best method for you depends on your purchase history, how long you have held various lots, your income bracket, and your tax goals. HIFO typically minimises current-year gains, while FIFO often produces more long-term treatment. Modelling each method against your actual transaction history — using crypto tax software — before selecting one is the most informed approach.
Can I change my cost basis method after already filing taxes?
Changing the cost basis method applied to prior transactions after filing requires formal IRS approval through a change in accounting method application — it cannot be done informally or by simply refiling an amended return with a different method applied. This process involves specific procedural requirements and is not guaranteed to be approved. For future transactions and new tax years, selecting a different method going forward may be possible in certain circumstances. This regulatory constraint makes the initial selection of a cost basis method a high-stakes decision. Choosing a method deliberately — after reviewing its impact on your specific portfolio with professional guidance — is far preferable to attempting to change it after the fact.
Does the cost basis method I choose apply to all my cryptocurrencies or just one?
The cost basis method is generally applied per asset — meaning you elect a method for each type of cryptocurrency in your portfolio rather than selecting one blanket method for all holdings simultaneously. This allows, in principle, for different methods to apply to different assets. However, consistency within each asset's transaction history is required: you cannot apply FIFO to some sales of Bitcoin and HIFO to others without formal documentation and IRS approval for the switch. In practice, most crypto tax software applies a single selected method uniformly across all assets, simplifying compliance and ensuring consistent documentation. If per-asset method flexibility is desired, working with a crypto-experienced CPA and detailed software is essential.
Common Misconceptions About Cost Basis Method
You can choose a different cost basis method each year to get the best tax outcome.
Selecting a different cost basis method year by year to retroactively optimise tax outcomes is not permitted. The IRS requires consistent application of the chosen method, and changing it for prior years requires formal approval through a change in accounting method procedure. While it may be possible to elect a different method going forward for new acquisitions in some circumstances, cherry-picking the most favourable method annually for the same asset history is not a valid approach. This consistency requirement reinforces why selecting the most suitable method from the outset — after modelling its impact on your specific portfolio — is significantly more valuable than attempting post-hoc optimisation.
The cost basis method only matters if you have a large number of transactions.
The cost basis method matters for any investor who holds the same cryptocurrency across multiple purchase lots acquired at different prices — regardless of how many total transactions they have. Even two purchases of the same coin at different prices create a scenario where the method choice affects which cost basis is applied to a partial disposal. An investor with just five transactions but two purchases of Bitcoin at very different prices could face meaningfully different tax outcomes under FIFO versus HIFO. The number of transactions is less important than whether multiple lot prices exist for the same asset — a condition that applies to most crypto investors who have been buying over time.
HIFO is always the correct cost basis method because it minimises taxes.
HIFO minimises current-year taxable gains in most scenarios, but it is not automatically the optimal method for every investor. Because HIFO assigns lots based on cost rather than holding period, it can produce short-term gains taxed at high ordinary income rates when the highest-cost lots were recently purchased. An investor in a high tax bracket may pay more total tax on a smaller short-term gain than on a larger long-term gain — because the rate differential more than offsets the gain size difference. The optimal method depends on the interplay between your specific lot history, your income bracket, and the holding periods of available lots — making per-investor modelling essential rather than assuming HIFO is universally superior.