Crypto cost basis calculator: which lots a disposal consumes, and what gain that produces
Enter your acquisition lots, pick a method, and enter a disposal quantity. The calculator shows which lots are consumed, the total basis relieved and, if you supply proceeds, the realised gain. It is a teaching aid for the mechanics of lot selection, not a sub-ledger and not a tax computation.
General information on accounting mechanics, not accounting or tax advice. Figures are illustrative. Verify against the applicable standards and your auditor.
Four methods on the lots you enter, for illustration. It applies no jurisdiction override, so it does not model UK Section 104 pooling with same-day and 30-day matching, Canadian adjusted cost base, or any other mandated treatment. Where local law mandates a basis, that rule governs regardless of the method chosen here. Not tax advice.
What the calculator does
A disposal of a fungible token is never a disposal of one identifiable thing. The entity holds a stack of acquisition lots, each with its own quantity, unit cost and acquisition fee, and the question the books have to answer is which of those lots the disposal relieved. That single choice sets the basis that leaves the balance sheet and therefore the gain or loss that hits the income statement. This tool makes the choice visible.
You enter a repeatable list of lots: quantity, unit cost and any acquisition fee. The fee is capitalised into the lot, so the unit basis is (unit cost x quantity + fee) divided by quantity, rather than being expensed on the side. You then choose a method and a disposal quantity, and optionally the proceeds. The output lists the lots consumed, the total basis consumed and, where proceeds are given, the realised gain.
The four methods it implements
- FIFO: oldest lots first. The default in many policies and the easiest to explain to a reviewer.
- LIFO: newest lots first.
- HIFO: highest unit cost first, which relieves the most expensive basis available.
- Weighted average: every lot is pooled into a single average unit cost, and the disposal draws on the pool.
A worked example
Take three lots of one unit each, acquired at 100, then 300, then 200, and dispose of one unit. FIFO consumes the 100 lot. LIFO consumes the 200 lot. HIFO consumes the 300 lot. Weighted average pools the three into a unit cost of 200 and relieves that. Same holding, same disposal, four different basis figures and therefore four different gains. The figures are illustrative.
| Method | Lot relieved | Basis consumed |
|---|---|---|
| FIFO | First lot (100) | 100 |
| LIFO | Third lot (200) | 200 |
| HIFO | Second lot (300) | 300 |
| Weighted average | Pooled across all three | 200 |
What this calculator cannot do
State this plainly, because it matters for anyone who might mistake the output for a computation they can file or post. The CryptaCount product supports twelve disposal cost basis methods plus automatic jurisdiction overrides, including UK Section 104 pooling with its same-day and 30-day matching rules, the Canadian adjusted cost base, and the French PFU treatment. This widget implements only the four methods whose mechanics can be demonstrated from a handful of typed lots, and it applies no jurisdiction override at all.
Where local law mandates a particular basis, that rule governs regardless of what you select here. A UK entity cannot simply choose HIFO because this page offers the button. See the full set of cost basis methods for what the engine actually applies and where each is appropriate.
- It does not read your wallets, exchanges or transaction history. You type the lots.
- It does not apply same-day, 30-day, pooling or averaging rules mandated by a jurisdiction.
- It does not handle crypto-for-crypto swaps, internal transfers, income receipts or fee tokens.
- It does not carry a running lot balance forward across multiple disposals.
- It produces no journal entry, no tax figure and no audit evidence.
Why it refuses an oversized disposal
If the disposal quantity exceeds the lots you entered, the tool stops and tells you the acquisition history is incomplete. It does not fall back to a zero basis for the shortfall. That fallback is the single most common way a naive crypto calculation manufactures a gain that never happened: a missing wallet or an unimported exchange export becomes a disposal with no cost, and the whole quantity is booked as profit. Refusing is the correct behaviour, and the same discipline applies in the sub-ledger, where an incomplete history is flagged rather than silently priced at nil.
Using it in practice
The realistic use is a conversation. A client asks why the gain moved when nothing about the sale changed, and you show them three lots and one disposal producing three answers. Or you are documenting an accounting policy and you want the method's effect on a real position in front of you before you write the paragraph.
What it is not is a substitute for a per-lot ledger. Across hundreds of disposals, several wallets and multiple assets, the method has to be applied deterministically and re-applied whenever data is corrected or a wallet is added late. That is a systems problem, not a spreadsheet problem.
Once you have a basis figure, the next step is the posting. The journal entry generator takes a basis and proceeds and returns the balanced double entry. If the disposal is being measured rather than sold, the fair market value calculator shows how much the answer moves with the price source you pick. The profit calculator and the Ethereum gas fee calculator cover the simpler arithmetic, and all five sit on the free tools hub.
The number a cost basis method produces is only defensible if the same method was applied to every disposal in the period, from a complete transaction history.
How CryptaCount handles this properly
CryptaCount is a crypto sub-ledger for finance teams. It ingests on-chain and exchange activity, maintains the per-lot history, applies your chosen method with the correct jurisdiction override across 72 mapped tax jurisdictions, and posts the resulting entries to IFRS and US GAAP ledgers and out to QuickBooks, Xero, NetSuite, Sage or Zoho. Every gain figure traces back to the lots that produced it.
FAQ
Which cost basis method should we use?
That is a policy and jurisdiction question, not a preference. Some jurisdictions mandate a specific treatment, such as UK Section 104 pooling with same-day and 30-day matching. Where a choice exists, it should be documented in the accounting policy and applied consistently to every disposal. See the cost basis methods guide for the full set.
Why does this tool only offer four methods when the product supports twelve?
Because four are all that can be demonstrated honestly from a few typed lots. The remaining methods and the jurisdiction overrides depend on dates, holding periods and pooling rules that require a complete transaction history, which a browser widget does not have.
Are acquisition fees included in the basis?
Yes. The fee entered against a lot is capitalised into that lot, so the unit basis is the total cost including the fee divided by the quantity. A fee paid to acquire generally forms part of cost basis rather than being expensed, though the precise treatment follows your policy and framework.
Can the output be used as audit evidence?
No. It is an illustration built from figures you typed, with no source data, no lot ledger and no jurisdiction rules behind it. Audit evidence has to trace to the underlying transactions and to a method applied consistently across the whole period.