HMRC Section 104 Crypto Pooling Calculator
✓ 2026/27 HMRC Tax Year VerifiedCalculate your allowable cost basis and chargeable capital gains under official HMRC Crypto Share Matching Rules (Taxation of Chargeable Gains Act 1992 s.104). Automatically applies the Same-Day Rule, the 30-Day Bed & Breakfast Rule, and tracks your Section 104 average pooled cost basis across multiple crypto trades.
Section 104 Pool & Trade Details
Section 104 Pool Ledger Status
📌 Key UK Crypto Share-Matching & Pooling Rules (2026/27)
- Statutory Matching Hierarchy: Disposals must be matched in strict order: 1. Same-Day Rule → 2. 30-Day Bed & Breakfasting Rule → 3. Section 104 Pool.
- Weighted Average Cost Basis: All tokens in a Section 104 pool share a single average cost. Buying new tokens updates the average cost per unit; selling tokens reduces pool size and total cost proportionally without changing the per-unit cost.
- Allowable Transaction Fees: Exchange trading fees and blockchain network gas fees incurred during acquisition are added directly to the allowable pool cost basis, reducing future capital gains.
- NFT Non-Pooling Exception: Non-Fungible Tokens (NFTs) are unique assets and cannot be pooled under Section 104; each NFT maintains its own standalone purchase price and sale ledger.
HMRC Crypto Share-Matching Rules: The 3-Tier Hierarchy
Under the Taxation of Chargeable Gains Act 1992 (TCGA 1992) and HMRC Cryptoassets Manual (CRYPTO22100 to CRYPTO22300), UK taxpayers cannot use FIFO (First-In, First-Out), LIFO, or cherry-pick tokens to minimize tax. When disposing of cryptocurrency, you must match your disposal against acquisitions in the following statutory sequence:
Tier 1: The Same-Day Rule (TCGA 1992 s.105)
1st PriorityTokens of the same cryptocurrency acquired on the exact same calendar day as the disposal are matched first. If you buy 1 BTC in the morning for £50,000 and sell 1 BTC in the afternoon for £52,000, your allowable cost is £50,000 (gain = £2,000), leaving your historical Section 104 pool untouched.
Tier 2: The 30-Day “Bed & Breakfasting” Rule (TCGA 1992 s.106A)
2nd PriorityIf there are no same-day acquisitions, the disposal is matched against any tokens of the same cryptocurrency acquired in the 30 days following the disposal date. This anti-avoidance rule prevents investors from selling tokens at a temporary loss on day 1 to claim tax relief and immediately rebuying on day 2. The cost basis equals the price paid for the replacement tokens.
Tier 3: The Section 104 Holding Pool (TCGA 1992 s.104)
3rd Priority (Default)All remaining tokens of a specific cryptocurrency (e.g. all historical Bitcoin or Ethereum) are pooled together into a single collective holding. The allowable cost basis of the disposed tokens is calculated as the weighted average acquisition cost of the pool at the moment of disposal.
Step-by-Step Worked Example: Section 104 Pool Ledger Simulation
Here is how an HMRC Section 104 crypto ledger updates dynamically across multiple purchase and disposal events:
The NFT Exception: Why Non-Fungible Tokens Are Not Pooled
Under HMRC Cryptoassets Manual (CRYPTO22110), Section 104 pooling applies only to fungible tokens—assets where one unit is completely identical to and interchangeable with another (such as 1 BTC or 1 ETH).
Non-Fungible Tokens (NFTs) represent unique digital assets (e.g. digital artwork, domain names, in-game items). Because each NFT has distinct metadata and attributes, each individual NFT is treated as a separate chargeable asset. You cannot pool NFTs—even if they belong to the same collection (e.g. two separate Bored Apes or Punk NFTs). You must track the specific purchase price and disposal proceeds for each token individually.
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Frequently Asked Questions About Section 104 Crypto Pooling
Do I maintain a separate Section 104 pool for every cryptocurrency?
Yes. You must create and maintain a distinct, separate Section 104 pool for each cryptocurrency you own (e.g. one pool for Bitcoin, one pool for Ethereum, one pool for Solana, and one pool for each stablecoin or altcoin). You cannot combine different tokens into a single multi-asset pool.
Why did HMRC introduce the 30-Day Bed & Breakfasting rule?
Under TCGA 1992 s.106A, the 30-Day rule prevents "tax-loss harvesting" abuses where an investor sells a depreciated token on day 1 to trigger an artificial capital loss on paper, and immediately buys back the exact same token on day 2. The rule matches the sale with the repurchase, neutralizing the artificial loss.
Do blockchain network gas fees get added to my Section 104 pool?
Yes. Under TCGA 1992 s.38, allowable costs include any costs wholly and exclusively incurred in acquiring the asset. When you buy tokens via a decentralized exchange (DEX) or pay exchange trading commissions, both the purchase price and the gas fees increase the total allowable cost in your pool, raising your average cost per token.
What happens to my pool when I transfer crypto between my own wallets?
Transferring tokens between your own private wallets or exchange accounts (e.g. Binance to Ledger) does not affect your Section 104 pool. Because beneficial ownership remains unchanged, it is not a disposal. The units held and total pool cost carry forward undisturbed.
How We Calculated This
- Input variables: Enter the relevant amounts, rates, or percentages in the form.
- Real-time breakdown: The calculator applies HMRC rules and thresholds for the 2026/27 tax year to process the values.
- Display outputs: The visual graphs, donut charts, and tables are compiled dynamically to show your net take-home and deductions.
Real-World Examples
A basic calculation applying standard UK tax bands and allowances.
Calculation runs based on standard HMRC rules.
Factoring in a percentage of salary sacrifice or pension contributions.
Deductions are calculated and adjusted accordingly.
Frequently Asked Questions
Yes, all calculators are fully updated with the latest HMRC thresholds, personal allowances, and National Insurance rates for 2026/27.
These tools are for estimation and illustrative purposes only. For official tax returns, please consult a qualified accountant or reference HMRC directly.