You sell, the money lands, and only then does the tax question turn up. The awkward part is that the records you now need were created one transaction at a time over the previous months or years — and by the time you go looking, they're often incomplete. A platform redesigned its export, an account got closed, and you genuinely cannot remember which address that transfer went out from.

So this piece doesn't try to tell you how much you owe. That depends entirely on where you file, and no single article can answer it — one that claims to shouldn't be trusted. What it does is get two things right that are entirely within your control today: recognising which actions can create a tax event, and capturing the records while they still exist.

1. What this can and can't do for you

Boundaries first. We are not tax advisers and we have never filed a return on anyone's behalf. What this article does is read two public, current, frequently updated official sources against each other: the IRS digital assets page, and the UK's gov.uk guidance on paying tax when you sell cryptoassets.

The point of picking those two isn't that you necessarily file in either country. It's that their specifics are wildly different — different taxes, different rates, different allowances, different methods for working out what a coin cost you. Two systems that far apart nonetheless agree closely on which actions count as a disposal and which fields you need to have kept. That overlap is what we're willing to write about, and it's all we write about.

This is not tax adviceYour obligations follow your tax residency and local law. They have nothing to do with which exchange you used, where it's incorporated, or what language the interface was in. Don't apply anything below directly to a return. Use it to work out what questions to ask and what paperwork to bring when you ask them.

2. What counts as a "disposal"

Disposal is the load-bearing word. The moment you sell, swap or spend a holding, you generally settle up: what it's worth now, what it cost you to get, and the difference is the gain or loss on that event.

Selling for cash is only one of the shapes it takes. Both sources list four:

  • Selling for fiat. The obvious one — coins out, dollars or pounds in.
  • Swapping one crypto for another. The IRS lists disposing of, selling, exchanging or transferring ownership of a digital asset "for another digital asset" among the situations requiring a Yes. gov.uk puts "exchanging them for a different type of cryptoasset" straight into its disposal list. This is the one that gets missed.
  • Paying with crypto. Buying goods or services with coins counts in both places. In effect you sold the coins and spent the proceeds, in one motion.
  • Receiving crypto as income. As payment, as a reward or award, or from activities like mining and staking. This category is usually valued at the market price when you received it and works differently from the three above; the UK has a separate guidance page for receiving cryptoassets.
Why the swap keeps slipping throughBecause your cash balance never moves. You trade USDT for BTC and two numbers swap places on a screen; nothing enters or leaves a bank account, so it doesn't feel like an event. Under both rule sets it already is one: the USDT leg is settled at that moment, and the BTC starts a fresh acquisition price from there. Someone who rotates positions regularly can rack up dozens of these settlement points in a year without registering a single one.

Worth separating out, because people conflate them: moving coins between your own accounts, or out to your own wallet, is generally not a disposal. Ownership didn't change hands; the coins just changed location. It creates no settlement point — but it does create a gap in your records, which is section 4.

3. Cost basis decides the number

One side of that difference is what you received. The other is cost basis: what the holding actually cost you to acquire, normally the purchase price plus the fees you paid on the way in.

Here's a deliberately labelled hypothetical. Say you buy for 1,000 units of your local currency and pay 2 in fees, making your cost basis 1,002. Later you sell for 1,400 and pay 3 in fees, netting 1,397. The gain on that disposal is 1,397 − 1,002 = 395. Fees move the number at both ends, so they aren't rounding noise — our piece on how trading fees are calculated breaks down the layers, and your records should give fees their own column.

Same coins, different arithmetic by countryThat formula is the general shape, but "which of my units did I just sell" is answered differently everywhere. Some systems use first-in-first-out, some let you identify specific lots, and the UK pools holdings of the same asset and works from the pooled cost. Don't copy any article's method, this one included — it has to match where you actually file. All you need to do now is capture the date, quantity and price of every acquisition, so that whichever method applies, the arithmetic is possible at all.

4. Exchange records break in three places

This is the part we most want you to take away. People assume they'll "just export a report at the end", but a platform can only tell you what happened on its own books. Do any of the following and that export is structurally incomplete:

1. Every deposit and withdrawal

When coins arrive from elsewhere, the platform sees an amount landing. It has no idea what you paid to acquire them, so it cannot work out your cost basis. And once coins are withdrawn, it has no idea what happened next — sold, swapped, or sitting untouched, it can't tell.

2. Anything spanning two platforms

Buy on A, move to B, sell on B: A holds the purchase price and no ending, B holds the sale price and no origin. Both halves are incomplete, and the only person who can join them is you.

3. Self-custody and on-chain activity

Once coins are in your own wallet, everything that follows is invisible to any exchange. That stretch has to be rebuilt from your own wallet records and the transaction hashes on-chain.

The export is raw material, not a finished statementTreat it as evidence of "what I did at this one venue during this period", not as a complete year-end position. Every action we describe elsewhere on this site — moving coins to your own wallet, choosing a network to withdraw over, selling and cashing out to fiat — leaves one of these joints in your records for you to weld shut. They're easy to close at the time and hardest to close years later.

5. The fields worth keeping

Whatever jurisdiction you end up in and whether or not you use tracking software, these fields are common to all of it. Capture them each time something worth recording happens:

  • Timestamp — date and time, with the time zone noted. Transactions near the end of a tax year deserve extra care.
  • Action type — buy, sell, crypto-to-crypto swap, payment, income, transfer in, transfer out. The transfers usually settle nothing, but leave them out and nothing reconciles later.
  • Asset and quantity — to the decimal places the platform shows. Don't round.
  • Fiat price and total at the time — what you actually paid or received. For a swap, note the fiat value of both legs as at that moment.
  • Fees — the amount, and which asset it was charged in.
  • Venue or counterparty — which platform, which account.
  • On-chain details — for anything that touched a chain: transaction hash, sending address, receiving address, and the network you selected. The hash is the most durable clue you'll ever have, because a block explorer will still have it years from now.
Two habits people skipFirst, save the untouched original export every time, not just your tidied-up spreadsheet. After a platform redesign, an account closure or a market exit, the history may simply not be exportable any more. Second, export on the rhythm of your activity rather than the calendar: if you traded a lot in March, pull March's data in March. Don't count on collecting a full year in one go.

On how long to keep it: the IRS general guidance on how long to keep records starts at three years, longer where substantial income has been under-reported. Check the period that applies where you are. But note the crypto-specific twist: as long as you still hold a coin and haven't disposed of it, the record of acquiring it has to survive indefinitely, however many years pass.

6. Four things people get wrong

1. "I never cashed out, so there's nothing to declare"

Swaps and payments count as disposals in both sets of guidance, regardless of whether money ever reached a bank account. This is the costliest misunderstanding here, because it doesn't affect one transaction — it affects every swap you made all year.

2. "It's a small amount, it doesn't matter"

Thresholds do exist — the UK has a capital gains allowance, other places have their own starting points — but the threshold is set where you file, not by your intuition about what counts as small. And "do I need to report" and "do I need to pay" are separate questions: under some systems a filing obligation survives even when the tax due works out to nothing.

3. "The exchange will give me a complete statement"

See the previous section. If you've ever deposited, withdrawn or moved between platforms, what you get back is half a picture.

4. "Nobody can see it anyway"

This one is expiring. Jurisdictions are implementing the Cryptoasset Reporting Framework (CARF): crypto service providers collect their users' activity and tax residency, report it to their own tax authority, and the parts concerning foreign users get exchanged with other jurisdictions that have implemented CARF. The UK's implementation note states the measure takes effect on 1 January 2026. Countries are at different stages, and you don't need to memorise any dates. You need to know that planning around invisibility is planning around an assumption with an expiry date.

7. When to hand it to a professional

What this article covers is day-to-day record keeping. For any of the following, go to a qualified tax professional where you file rather than working it out yourself:

  • the amounts involved are significant to you;
  • you hold more than one nationality, moved country during the year, or have income in two places, so your residency itself isn't obvious;
  • you have income-type receipts — mining, staking, airdrops, lending interest — which are treated differently from buying and selling;
  • you want to use losses against gains, which is usually far more intricate than the rules for gains alone;
  • you've already had a query or notice from a tax authority;
  • your history has holes and needs rebuilding.

That last one is worth pre-empting: cost basis reconstruction is a routine professional service, and it costs more the longer you wait, because the source material keeps thinning out. Ten minutes spent exporting a CSV today can save a real invoice a few years from now.

How we checked thisThe factual parts were checked line by line on 2026-08-30 against five official pages: the IRS digital assets page and its record-retention guidance, plus the gov.uk pages on selling cryptoassets, receiving cryptoassets, and CARF implementation. We have never filed a return for anyone and hold no tax qualification in any country, which is exactly why there are no rates here, no allowances, and no instructions for filling in a form — those change yearly, and getting them wrong is your problem, not ours. What is stable, consistent across very different systems, and only you can do, is recognising the events and keeping the records. That part we've written out in full. The rest belongs with someone qualified where you live.
Three things you can finish today
Export a full transaction history from every platform you currently use and save it locally. For every coin you still hold, check whether you can actually evidence when and at what price you acquired it. And if your holdings are spread across several venues, read what a second exchange account really costs you — records split into disconnected halves is one item on that list.

Nothing in this section recommends opening an account anywhere. This article is not tax, legal or investment advice; your obligations follow your local rules and any professional advice you obtain.

Back to Withdraw

8. A one-page action list

  • Record swaps and payments as potential disposals, not just cash-outs;
  • capture all seven fields — timestamp, action, asset and quantity, fiat value, fees, venue, on-chain hash;
  • export regularly and keep the original file, rather than waiting for year-end or for the day you need it;
  • transfers usually aren't disposals but still need recording, or the cross-platform stretch never reconciles;
  • while a coin is still unsold, keep its acquisition record indefinitely;
  • for large amounts, complex residency, income-type receipts or missing history, get local professional help instead of estimating.

You'll notice nothing here is about paying less. The only part that's genuinely yours to control is whether every event that happened is still retrievable when you need it. Get that right and any rule set can be applied; get it wrong and even a simple one becomes impossible to work out.

9. FAQ

I only swapped USDT for BTC and never cashed out. Does that count?

In both sets of guidance we read, yes. The IRS digital assets page lists disposing, selling, exchanging or transferring ownership of a digital asset for another digital asset among the situations that make you answer Yes. UK gov.uk puts exchanging them for a different type of cryptoasset directly in its disposal list. This is the one beginners miss most often, because no money moved in or out of a bank and it feels like nothing happened. Whether your own jurisdiction treats it the same way is for your tax authority to say, but keeping the record as if it counts costs you almost nothing.

Can I just hand my exchange's CSV export to my accountant?

As raw material, yes. As a finished statement, no. An exchange only knows what happened on its own books. If coins arrived by deposit, it has no idea what you paid to acquire them, so it cannot compute your cost basis. If coins left by withdrawal, it has no idea what you did with them afterwards. Anything that happened on another platform or in your own wallet is invisible to it. So the moment you have deposited, withdrawn or moved between platforms, that export is missing pieces, and you are the only person who can supply them.

I bought years ago and my records are gone. What now?

Lock down everything still reachable first: export whatever order and transfer history the platforms still hold, pull bank statements for the matching periods, and use transaction hashes to recover dates, amounts and addresses from a block explorer, which keeps them permanently. That usually reconstructs most of it. For whatever genuinely cannot be recovered, do not invent a number. Write down the method you used to estimate, keep the reasoning, and if the amounts are meaningful hand it to a qualified tax professional where you file. Cost basis reconstruction is a routine professional service, and it gets more expensive the longer you leave it.

Do I still have to report if I lost money?

In many systems, whether you must file and whether you end up owing anything are two separate questions, and a losing year can still carry a filing obligation. Where losses can be offset or carried forward, reporting them accurately works in your favour, but only if you have records to support them. The details vary a great deal by jurisdiction: whether losses are usable, for how long, and against what kind of gains all depend on where you actually file.

I live abroad. Whose rules apply to me?

Your tax residency and local law decide, not which exchange you used, where that exchange is incorporated, or what language you clicked through. If you hold more than one nationality, moved country during the year, or have income in two places, you may be looking at more than one set of rules at once. That is beyond what any general article can answer and belongs with a qualified professional where you live. This site only covers how to keep your records straight; it does not assess individual cases.

What you need on the day you sell was accumulated one transaction at a time over the preceding months. Recognise the four shapes a disposal takes, understand where cost basis comes from, know that exchange records break at deposits, cross-platform moves and self-custody, and capture the seven fields as you go. Done today, that's ten minutes. Done when you need it, it's a professional's invoice — or a gap that never closes.

Lin Yue · Bitu editorial
Notes on using crypto exchanges, written for beginners. Lin Yue is a pen name — we don't pretend to be anyone's expert, we just write down the steps and traps we've checked and re-checked. For anything involving money, go by the official pages and your own verification.

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