ChamTax is a free calculator that shows the actual after-tax take-home amount for US Powerball and Mega Millions jackpots. Here's how a US lottery win is taxed for a UK resident — a flat 30% US withholding that's generally final, and £0 additional tax from HMRC.
Last updated: 2026-08-19
$1,000,000 win, UK resident estimate
At a reference USD→GBP rate of roughly 0.74, that $700,000 take-home is about £517,000 — the calculator above converts your own amount using a live exchange rate.
No. HMRC doesn't tax gambling or lottery winnings at all — not as Income Tax, not as Capital Gains Tax, and there's no National Insurance charge either. This isn't a foreign tax credit offsetting some computed UK tax bill down to zero (the way it works for a few other countries this calculator covers); there's simply no UK tax base for gambling or lottery winnings in the first place, whether the prize comes from the National Lottery, EuroMillions, or a US Powerball or Mega Millions jackpot. So a UK resident who wins a US lottery jackpot owes £0 additional UK tax on top of whatever the US withholds.
The US taxes nonresident aliens on lottery winnings at a flat 30% federal withholding rate (IRC §871(a)) — higher than the 24%-withheld/37%-top-rate treatment that applies to US residents, and withheld immediately when the prize is paid out. The US-UK tax treaty doesn't lower that withholding rate at the moment your prize is paid, so a UK resident's US lottery win is withheld at the same standard 30% nonresident-alien rate as winners from most other countries this calculator covers — that's the amount you actually receive, and it's what this calculator's numbers reflect.
There may still be a way to reclaim some of it afterwards, though. The US Treasury Department's own official Technical Explanation of the US-UK tax treaty's 1975 Protocol (home.treasury.gov/.../Treaty-UK-Protocol-TE-7-22-2002.pdf) confirms that Article 22 ("Other Income") — which assigns taxing rights over income not covered elsewhere in the treaty exclusively to the taxpayer's country of residence — explicitly names "income from gambling" as an example of what it covers. That gives UK residents a plausible basis to file a US Form 1040-NR and claim some or all of the 30% withholding back after the fact. This isn't automatic: no state lottery commission is known to apply this treaty exemption in real time at payout the way some casinos do for repeat foreign gamblers, and it hasn't been confirmed by a documented case of someone completing this refund for a lottery win specifically (as opposed to the more established casino-refund process). A qualified cross-border tax adviser can confirm whether it's worth pursuing for your situation.
The prize itself is tax-free, but what you do with it afterwards can matter — specifically for UK Inheritance Tax (IHT) if you gift a large sum to family and later pass away. This is a general IHT rule that applies to any large gift, not something specific to lottery winnings, but it's worth knowing if you're planning to share a windfall.
Every individual has a nil-rate band of £325,000 (2026/27) — gifts within that band made in the 7 years before death owe no IHT regardless of timing. Above that band, what happens depends on how long you live after making the gift:
Taper relief reduces the tax charged on the gift, not the gift's value itself — it only comes into play once a gift is large enough to exceed the nil-rate band. This is general UK inheritance tax law and isn't specific to lottery winnings; if you're considering a large gift, a qualified UK tax adviser can walk through your specific estate.
Moving a large lump sum from the US into a UK bank account doesn't create any extra tax by itself, and unlike some countries there's no single fixed reporting threshold UK banks must hit. Instead, banks operate under the Money Laundering Regulations 2017 and the Proceeds of Crime Act 2002: they apply Enhanced Due Diligence to transactions that look unusually large or complex for the customer's normal activity, and can file a Suspicious Activity Report with the National Crime Agency at their own discretion if something looks off — there's no public number that automatically triggers either step. In practice, a six- or seven-figure inbound wire from a US lottery payout is exactly the kind of large, one-off transaction likely to prompt your bank to ask for proof of where the money came from before releasing it, even though there's no tax owed on the prize itself.
Keep your prize confirmation or payout documentation on hand — it's the easiest way to answer a bank's source-of-funds question quickly.
See your own after-tax amount as a UK resident
Open the calculator →The US withholds a flat 30% federal tax from a nonresident alien's lottery winnings (IRC §871(a)) before you ever see the money. On the UK side, HMRC doesn't tax gambling or lottery winnings at all — not as Income Tax, not as Capital Gains Tax, and no National Insurance either — so a UK resident owes £0 additional UK tax on top of that. The 30% US withholding is the whole story for most UK winners.
Yes. HMRC's non-taxation of gambling and lottery winnings applies equally to domestic prizes — the National Lottery, EuroMillions, Set For Life, scratchcards — and to a foreign win like a US Powerball or Mega Millions jackpot. The prize itself simply isn't treated as taxable income under UK law, regardless of where the ticket was bought.
The winnings themselves are tax-free, but large gifts you make afterwards can matter for UK Inheritance Tax (IHT) if you die within 7 years of making them — this is a general IHT rule, not specific to lottery winnings. Gifts within the £325,000 nil-rate band (2026/27) owe nothing regardless of timing. Above that, dying within 3 years of the gift means the excess is taxed at the full 40% IHT rate; dying 3-7 years after applies taper relief on a sliding scale (20% relief at 3-4 years, 40% at 4-5, 60% at 5-6, 80% at 6-7). Survive 7 years and the gift is fully outside your estate.
Possibly, via a US tax filing after the fact — it isn't automatic. The US-UK tax treaty's Article 22 ("Other Income") assigns taxing rights over income like gambling winnings exclusively to your country of residence, and the US Treasury's own official Technical Explanation of the treaty specifically lists "income from gambling" as an example of what the article covers. That gives UK residents a plausible basis to file a US Form 1040-NR and reclaim some or all of the 30% withheld at payout. It's not guaranteed, and it isn't as well-documented in practice as the refund process casinos sometimes offer repeat foreign gamblers, so it's worth getting a cross-border tax professional's advice before relying on it. Either way, the 30% is still what's withheld from your prize at the time you're paid — that's what this calculator's numbers show.
There's no lottery-specific rule, but a transfer this large puts you through your bank's ordinary anti-money-laundering process. Under the Money Laundering, Terrorist Financing and Transfer of Funds (Information on the Payer) Regulations 2017 — enforced by the FCA — UK banks carry out customer due diligence on transfers like this, which in practice means asking you to document where the money came from before crediting it. There's no single published threshold for when this kicks in (each bank makes a risk-based call), so expect questions for a sum this size; your prize claim paperwork and the IRS's Form 1042-S withholding statement are exactly the kind of documentation that satisfies it. If the bank's systems flag the transfer as unusual, it could lead to a Suspicious Activity Report to the National Crime Agency — a routine compliance step, not an accusation, and one a well-documented legitimate prize claim should clear without issue.
This page is an informational simulator only and does not broker or facilitate lottery ticket purchases. Actual tax owed depends on individual circumstances (including UK domicile status and Inheritance Tax planning) and the exchange rate/tax law in effect at filing time — consult a qualified tax professional familiar with both countries.