The IRS Changed Bitcoin Cost Basis Rules in 2025 — Here Is What That Means for Your 2026 Tax Bill

Starting January 1, 2025, the IRS requires all taxpayers to calculate Bitcoin cost basis on a per-wallet, per-account basis rather than pooling holdings across platforms. If you bought Bitcoin on three exchanges over five years and have been applying a single FIFO queue to all of it, your prior method is no longer IRS-compliant. The change affects how you match each sale to its corresponding purchase, which cost basis method you can apply to which assets, and whether your crypto tax software is producing accurate or incorrect figures.

Bitcoin cost basis calculation is the process of determining the original acquisition price of each unit of Bitcoin you dispose of, which in turn determines whether you have a taxable gain or a deductible loss and how large that gain or loss is. The formula is straightforward: cost basis equals the price you paid for the Bitcoin plus any fees paid to acquire it. The complexity arises when you have purchased Bitcoin at multiple prices over multiple years across multiple accounts and want to know which specific units you are deemed to have sold at the time of a given disposal.

This article explains every permitted crypto cost basis method under 2026 IRS rules, the critical distinction between covered and noncovered digital assets, how the per-wallet rule changes your recordkeeping obligations, and how to avoid the most common cost basis mistakes that result in overpaying tax.

What Bitcoin Cost Basis Includes

Your Bitcoin tax basis in a given unit of Bitcoin is the total of what you paid to acquire it. For a straightforward purchase on an exchange, this is the purchase price plus the exchange fee. If you bought one Bitcoin for $60,000 and paid a $100 trading fee, your cost basis is $60,100. When you later sell that Bitcoin for $75,000 and pay a $50 withdrawal fee, your amount realized is $74,950 and your taxable gain is $74,950 minus $60,100, which equals $14,850.

Cost basis also applies to Bitcoin received in non-purchase transactions. Bitcoin earned through mining has a cost basis equal to the fair market value on the day it was received, since it was taxed as ordinary income at that point. Bitcoin received as a gift carries over the giver's original cost basis (or the fair market value at the date of the gift, if lower, if you sell at a loss). Bitcoin acquired through a fork or airdrop has a cost basis equal to the fair market value on the date you received it, if the IRS treats the receipt as a taxable income event.

Fees That Affect Cost Basis

Transaction fees paid when buying Bitcoin increase your cost basis, which reduces your eventual taxable gain. Transaction fees paid when selling Bitcoin reduce your proceeds, which also reduces your taxable gain. Fees paid to transfer Bitcoin between your own wallets are generally not deductible and do not affect cost basis under IRS guidance for investors, because the IRS views these as non-deductible personal transfers. However, business entities that hold Bitcoin as part of a trading business may treat certain transfer costs differently on Schedule C.

The Two Permitted Methods Under 2026 IRS Rules

The IRS permits two cost basis methods for digital assets starting with the 2025 tax year: First-In-First-Out (FIFO) and Specific Identification. Specific Identification encompasses lot-selection strategies including Highest-In-First-Out (HIFO) and Last-In-First-Out (LIFO). Average cost basis, which is permitted for mutual funds, is not an approved method for Bitcoin or other cryptocurrencies.

First-In-First-Out (FIFO)

Under FIFO, the earliest Bitcoin you purchased within a given wallet or account is treated as the first Bitcoin sold when you make a disposal. FIFO is the IRS default. If you do not make an explicit election to use Specific Identification, the IRS assumes you are using FIFO. Starting in 2026, exchanges default to FIFO when reporting cost basis on Form 1099-DA unless you have documented a Specific Identification election.

FIFO tends to produce higher taxable gains in a market where Bitcoin's price has risen over time, because the earliest purchases typically have the lowest cost basis. For long-term holders who bought early, FIFO may result in more long-term capital gain (taxed at 0%, 15%, or 20%) rather than short-term gain (taxed as ordinary income), which is an advantage even if the gain amount is higher.

Specific Identification (Including HIFO and LIFO)

Specific Identification allows you to choose which specific units of Bitcoin you are selling at the time of each disposal. This is the method that enables HIFO and LIFO lot-selection strategies. Under HIFO, you identify the units with the highest cost basis as the ones you are selling first, minimizing taxable gain on each disposal. Under LIFO, you identify the most recently purchased units as the ones sold first, which can be advantageous in specific market conditions.

The critical IRS requirement for Specific Identification is that you must identify the specific lot at or before the time of the sale. You cannot apply Specific Identification retroactively after the tax year ends. Your crypto tax software must maintain lot-level records that document which specific units were identified for each sale. Selecting "HIFO" in your software settings does not automatically satisfy this requirement unless the software is generating and storing the corresponding lot-level identification records per transaction.

Covered vs. Noncovered Digital Assets: The 2026 Distinction

The 2026 Form 1099-DA framework introduces a distinction that has significant practical consequences for cost basis documentation.

Covered digital assets are Bitcoin and other cryptocurrencies acquired on or after January 1, 2026 and held on the same regulated broker platform. For these assets, the broker is required to report both gross proceeds and cost basis on Form 1099-DA when you sell. This mirrors the treatment of stocks and bonds, where brokers have reported cost basis since 2011.

Noncovered digital assets are Bitcoin acquired before January 1, 2026, or assets transferred onto a platform from a private wallet. For these assets, broker cost basis reporting on Form 1099-DA is voluntary rather than mandatory. Most exchanges will not report cost basis for noncovered assets in 2026.

The practical consequence is that if you sell Bitcoin on an exchange and the 1099-DA shows proceeds but no cost basis, you are responsible for providing your own cost basis documentation. If you cannot, the IRS may assess tax on the full proceeds as if your cost basis were zero. According to CryptoSlate's 2026 analysis of 1099-DA reporting, this scenario of "proceeds-only" forms is the primary source of unintentional crypto tax overpayment in the current filing season.

The Per-Wallet Rule

Under the January 2025 IRS per-wallet requirement, cost basis tracking is strictly segregated by account. You cannot take Bitcoin purchased on Exchange A and match it against a sale on Exchange B. Each sale must be matched against purchases made within the same wallet or account. This rule has two important implications. First, transferring Bitcoin from one exchange to another changes the tax treatment of the transferred asset, because once it arrives at the new exchange it becomes "noncovered" if it was purchased on the original exchange before 2026. Second, Bitcoin held in a hardware wallet that you transfer to an exchange for sale will always be noncovered for basis reporting purposes, regardless of when it was originally purchased.

How to Calculate Bitcoin Cost Basis Correctly in 2026

Step one is to export a complete transaction history from every exchange and wallet where you have held Bitcoin. Most exchanges provide a downloadable CSV of all trades, transfers, and receipts. Hardware wallet transaction histories can be imported using the wallet address in most crypto tax software.

Step two is to label every transaction type correctly. Purchases increase your inventory and create new cost basis lots. Sales dispose of lots and generate taxable events. Transfers between your own wallets move lots from one account-level ledger to another without creating a taxable event. Incorrect transfer labeling is the single most common source of phantom taxable gains in crypto tax software outputs.

Step three is to select your cost basis method per wallet per tax year and document that election. You must use the same method consistently within a given wallet for the entire tax year, but you can use different methods in different wallets and you can change your method from one year to the next.

Step four is to reconcile your calculated gains against your Form 1099-DA proceeds figures. Any discrepancy requires investigation before filing.

For anyone trading Bitcoin across multiple platforms, crypto tax software that performs automatic per-wallet matching and lot identification is the most practical way to implement these steps accurately at scale.

FAQ

What is cost basis for Bitcoin?

Cost basis for Bitcoin is the original acquisition price of a unit of Bitcoin plus any fees paid to acquire it. It is subtracted from your sale proceeds to calculate your taxable gain or deductible loss. If you paid $50,000 for one Bitcoin plus $100 in fees, your cost basis is $50,100. Cost basis determines both the size of your taxable gain and whether that gain qualifies for the lower long-term capital gains rate.

What cost basis methods does the IRS allow for Bitcoin?

The IRS permits two methods for digital assets: FIFO and Specific Identification. Specific Identification includes HIFO and LIFO as lot-selection strategies. Average cost is not permitted for Bitcoin. FIFO is the default method. Specific Identification requires you to identify the exact lots being sold at or before the time of each sale and maintain supporting records.

What is the per-wallet cost basis rule?

The IRS per-wallet rule, effective January 2025, requires that each Bitcoin sale be matched against purchases made within the same wallet or account. You cannot pool Bitcoin across different exchanges and apply a single cost basis queue. Each account maintains its own cost basis inventory. This makes multi-account tracking more complex and makes crypto tax software that performs per-wallet reconciliation effectively mandatory for active traders.

What are covered vs noncovered digital assets?

Covered digital assets are Bitcoin acquired on or after January 1, 2026 on a regulated broker platform. Brokers must report both proceeds and cost basis for covered assets on Form 1099-DA. Noncovered digital assets are Bitcoin acquired before 2026 or transferred from a private wallet. Brokers are not required to report cost basis for noncovered assets, meaning you must provide your own documentation.

How do I avoid overpaying tax on Bitcoin because of wrong cost basis?

Maintain complete transaction records from every exchange and wallet, label all inter-wallet transfers correctly to prevent them from appearing as sales, elect Specific Identification with HIFO if you want to minimize gains and maintain the required lot-level documentation, and reconcile your calculated gains against your Form 1099-DA before filing. Using dedicated crypto tax software that performs per-wallet matching is the most reliable way to implement all of these steps accurately.

Conclusion

Bitcoin cost basis calculation in 2026 is more complex than it has ever been, primarily because the per-wallet IRS rule eliminated the simplified pooled-inventory approach that many traders previously used. The covered vs. noncovered distinction adds a second layer of complexity for anyone who bought Bitcoin before 2026 or moves it between self-custody and exchange accounts. Getting these calculations right is not just a compliance obligation — it is the primary lever for legally minimizing your Bitcoin tax bill through proper method selection and accurate basis documentation.

The most consequential action you can take right now is to reconcile your complete transaction history across all wallets and exchanges before next filing season, and to verify that the cost basis method documented in your records is the one your software is actually applying per wallet.

For traders starting fresh on a compliant platform with clean, importable transaction records, the BYDFi guide to buying BTC walks through account setup from the beginning. For live Bitcoin market pricing that informs cost basis records for new purchases, the BYDFi Bitcoin price overview provides real-time data.