Cost Basis Methods Explained: FIFO, LIFO, and Specific Identification for Crypto
Cost Basis Methods Explained: FIFO, LIFO, and Specific Identification for Crypto
When you sell crypto, your taxable gain isn't simply the amount you received from the sale.
You also need to know which crypto you sold and what it originally cost you.
That's where cost basis methods come in.
The three methods you will commonly hear about are FIFO (First In, First Out), LIFO (Last In, First Out), and Specific Identification.
The method you use can affect the gain reported on a transaction and therefore your tax bill.
What is cost basis?
Cost basis is generally the amount you paid to acquire an asset, adjusted where applicable for things such as transaction costs.
In simple terms:
Cost Basis = What You Paid for the Crypto + Applicable Costs
When you later dispose of the crypto, the cost basis is compared with the proceeds from the disposal.
For example:
You buy 1 ETH for $2,000.
Later, you sell that ETH for $3,000.
Your gain is:
$3,000 − $2,000 = $1,000
The calculation becomes more complicated when you've bought the same asset multiple times at different prices.
Imagine you bought:
- 1 ETH for $2,000
- 1 ETH for $2,500
- 1 ETH for $3,000
You then sell 1 ETH for $4,000.
Which purchase should be used to calculate your gain?
That's where the cost basis method matters.
FIFO: First In, First Out
FIFO assumes that the crypto you sell first is the crypto you acquired first.
Using the example above, selling 1 ETH for $4,000 would use the earliest purchase:
$4,000 − $2,000 = $2,000 gain
FIFO is relatively straightforward and is often the default approach in systems that need to assign lots automatically.
LIFO: Last In, First Out
LIFO works in the opposite direction.
It assumes the most recently acquired crypto is sold first.
Using the same example, the $3,000 purchase would be matched with the $4,000 sale:
$4,000 − $3,000 = $1,000 gain
That produces a very different result from FIFO.
LIFO is not automatically permitted for crypto tax reporting in every country. Before applying LIFO to an actual tax return, you should confirm that the method is permitted under the applicable tax rules.
Specific Identification
Specific Identification allows you to identify the particular units or lots that were sold, subject to the rules that apply in your jurisdiction.
For example, if you have three ETH acquisition lots, you may be able to identify exactly which lot was disposed of.
This can provide more control over which cost basis is used.
However, it also requires accurate transaction records and the ability to identify and substantiate the relevant assets.
FIFO vs LIFO vs Specific Identification: Simple Comparison
| Method | Basic Concept | Example |
|---|---|---|
| FIFO | First acquired, first disposed | Oldest ETH lot is matched first |
| LIFO | Last acquired, first disposed | Newest ETH lot is matched first |
| Specific Identification | Identify the particular acquisition lot disposed of | A particular ETH acquisition is matched to the sale |
The important point is that the same crypto sale can produce a different gain depending on which cost basis is assigned to the asset sold.
So which method is best?
There isn't one answer that works for everyone.
The treatment and permitted methods can vary depending on where you live and the tax rules that apply to you.
The important thing is to understand the method being used and make sure your transaction history supports it.
This becomes particularly important when your crypto activity spans multiple exchanges and wallets.
Where crypto cost basis gets complicated
The method itself is only part of the problem.
Before you can apply FIFO, LIFO or Specific Identification, you need reliable transaction data.
If the original purchase is missing, the software may not know the correct cost basis.
If you've transferred crypto between your own wallets, the acquisition history can become disconnected.
If you've imported the same exchange history twice, duplicate transactions can distort the calculation.
And if you've moved assets through DeFi protocols, bridges or wrapped tokens, determining the correct underlying transaction history can require additional reconciliation.
In other words:
A cost basis method can only produce a useful result if the underlying data is correct.
The bottom line
FIFO, LIFO and Specific Identification aren't just technical accounting terms.
They determine how your crypto acquisitions are matched to your disposals and can therefore have a significant impact on reported gains.
Before focusing only on which method you're using, make sure the underlying transaction history is complete, accurate and properly reconciled.
For investors with multiple exchanges, wallets and years of trading history, cost-basis reconciliation is often the most important step before preparing the final crypto tax report. Because if the software is matching the wrong purchase to the wrong sale, even the correct cost basis method can produce the wrong answer.