The step
Since August 2023 all alcoholic drinks in the United Kingdom have been taxed on the alcohol they contain, in bands. For beer the band that matters sits at 3.5%. HM Revenue and Customs publishes the rates, and the two bands either side of that line are not close together.
| Strength | Rate |
|---|---|
| 0% to 1.2% | 0.00 |
| 1.3% to 3.4% | 9.96 |
| 3.5% to 8.4% | 22.58 |
| 8.5% to 22% | 30.62 |
Rates as published by HM Revenue and Customs, page last updated 1 February 2026, for beer that is not sold on draught. The draught rates are lower, and the one this guide quotes is discussed below.
A tenth of a percentage point of strength moves a beer from one band to the other, and the rate it pays more than doubles. That is not a subtle incentive. It is the largest single lever a brewer has over the cost of a can, short of changing what is in it.
What it is worth, per can
The arithmetic is short enough to do here. Duty is charged on the pure alcohol in the container: the volume multiplied by the strength gives litres of pure alcohol, and that is multiplied by the rate for the band. For a 440ml can:
| Strength | Litres of pure alcohol | Band rate | Duty on the can |
|---|---|---|---|
| 3.4% | 0.01496 | 9.96 | 14.9p |
| 3.5% | 0.01540 | 22.58 | 34.8p |
A tenth of a percent weaker saves about 19.9p of duty on every can, roughly 80p on a four-pack and about £2 on a pack of ten. Multiply that across a national brand and the reason for the cluster is no longer mysterious. None of that is hidden: the rates are published, and the calculation is the same one any brewer does.
What changed in 2023
The bands are recent. HM Revenue and Customs describes the reform as creating "standardised tax bands based on alcohol by volume", and says the new structure "will take effect from 1 August 2023". Before that, beer duty worked differently and the thresholds sat elsewhere. Several of the strength cuts recorded on this site happened in the two years after that date, which is what you would expect when the shape of the tax changes.
One brewer has said so directly. The entry for Carlsberg Danish Pilsner records that it was 3.8% from the 2019 relaunch until 2023, when it was cut to 3.4% to sit inside the lower band introduced on 1 August 2023. Grolsch was relaunched in the UK at 4.0% in 2020 and cut again to 3.4% in October 2024, which Asahi linked to sliding sales and the duty band below 3.5%.
The cluster
Plotted on a strength axis, the effect is a local spike. 11 of the beers on this site sit at exactly 3.4%. On either side there is almost nothing: one beer at 3.3% and one at 3.5% itself. There are taller stacks further up the axis, at the strengths lager is normally brewed to, but nothing else in the dataset piles onto a single tenth of a percent the way this does.
The numbers behind the chart
| UK strength | Beers | Of which sold as foreign and brewed here |
|---|---|---|
| 3.3% | 1 | 1 |
| 3.4% | 11 | 5 |
| 3.5% | 1 | 0 |
| 3.6% | 3 | 0 |
| 3.8% | 3 | 1 |
| 4.0% | 6 | 3 |
| 4.1% | 4 | 0 |
| 4.2% | 4 | 0 |
| 4.3% | 1 | 0 |
| 4.4% | 3 | 1 |
| 4.5% | 12 | 5 |
| 4.6% | 9 | 6 |
| 4.7% | 7 | 1 |
| 4.8% | 13 | 4 |
| 4.9% | 1 | 0 |
| 5.0% | 16 | 5 |
| 5.1% | 1 | 0 |
| 5.2% | 2 | 0 |
| 5.3% | 1 | 0 |
| 5.4% | 1 | 0 |
| 5.5% | 3 | 0 |
| 5.6% | 1 | 0 |
| 5.9% | 1 | 1 |
| 6.0% | 1 | 0 |
The 11 are Amstel, Banks's Amber Bitter, Boddingtons Draught Bitter, Bud Light, Carlsberg Danish Pilsner, Coors Lager, Foster's, Greene King IPA, Grolsch Premium Pilsner, Rosa Blanca and Sol. They have little else in common: a Dutch pilsner, an Australian brand brewed in Manchester, an American light lager, a Mexican brand brewed in Britain, a Spanish beer that really is brewed in Spain, and a Manchester bitter. What they share is a number.
Some of them arrived there from higher up. Foster's was cut twice, from 4.0% to 3.7% in January 2023 and from 3.7% to 3.4% by February 2026. Rosa Blanca is the odd one out: it is genuinely brewed in Spain and imported, and still arrives at 3.4% against 4.8% at home. Brewing abroad does not exempt a beer from British duty.
Why the pub pint is different
The same reform introduced a lower rate for draught products. A beer between 3.5% and 8.4% pays £22.58 per litre of pure alcohol in a can and £19.45 on draught. That is why a brand can be one strength in the supermarket and another in the pub, and why the pressure to drop under 3.5% is felt hardest in the off-trade. Where a beer differs by format, the entry for it says so.
What this does and does not tell you
It is worth being precise about the claim. The duty bands are published, the strengths are on the packs, and the cluster at 3.4% is a fact you can check from both. That a given brewer cut a given beer because of the bands is a different claim, and this site only makes it where a brewer or the trade press has said so.
25 beers on this site are weaker in Britain than in their home market, and the full comparison is on the strength page. Duty explains a good deal of it. It does not explain all of it, and where a beer is weaker here for some other reason, its own page says what the sources actually support.