# Beer GP Calculator: Keg Yield, Wastage and Margin Per Pint

> A keg holds more pints than you can sell out of it. This calculator converts keg size to saleable pints, applies your line wastage, strips the VAT off the pint price, and gives you the GP you actually take.

- Author: Alex Riesenkampff (Super44)
- Published: 2026-08-21
- Canonical: https://super44.ai/blog/beer-gp-calculator

## Key takeaways

- A 50-litre keg holds 87.99 pints, because the Weights and Measures Act 1985 defines a pint as 0.56826125 of a litre.
- Saleable pints are fewer than that: at 5% line and cellar wastage a 50-litre keg yields about 83.6 pints, which raises the cost per pint on a £120 keg from £1.36 to £1.44.
- Leaving wastage out of the sum overstates draught GP by almost two percentage points: 66.1% against an actual 64.3% on a £4.83 pint.
- Cask is a different container, and the trade shorthand misleads: a firkin is nine imperial gallons, 40.9 litres and 72 pints. Enter 50 litres for a firkin and you understate cost per pint by more than a fifth.
- Glassware changes the sum. Aberdeenshire Trading Standards cites the BBPA's position that a pint should contain a minimum of 95% liquid and 5% head, so a brim glass poured with a head takes about 0.95 pints of liquid and a 50-litre keg stretches to roughly 92.6 servings instead of 88.
- If you are tied, the folklore bands were never describing you. UKHospitality and Christie and Co found wet-sales GP of 61.2% for estates on mainly tied leases against 68.9% for those on commercial leases, which the report puts at 7.8 percentage points. It also warns its tied-lease sample is limited.

A 50-litre keg holds 87.99 pints, and you will not sell 87.99 pints out of it. The gap between the beer you buy and the beer that reaches a glass is what separates draught GP from every other kind, and it is the step most calculators leave out. At 5% wastage that keg yields about **83.6 saleable pints**, which turns a £120 keg from £1.36 a pint into **£1.44**, and a draught GP of 66.1% into **64.3%**.

**GP per pint, after keg yield and wastage** *(interactive calculator in the web version)*

Example (Keg cost, ex-VAT: 120 £, Keg size: 50 litres, Line and cellar wastage: 5 %, Price per pint, VAT included: 4.83 £, VAT rate: 20 %, Pints of this line you sell in a week: 300):

- Pints in the keg: 87.99
- Saleable pints after wastage: 83.59
- Cost per saleable pint: 1.44 £
- GP percentage: 64.3 %
- What your wastage costs on this line in a year: 1,120 £
- Gross profit from this line in a year: 40,395 £

*Gross profit on the beer only. Gas, cooling, cleaning chemicals and the labour to clean lines are real costs of running draught, and they sit below this line.*

Every number above is a forecast. The keg cost is on an invoice, the wastage is an estimate, and the GP is what should happen if the estimate is right.

The figure that settles it is on your till, and it usually arrives too late to act on. A line running two points below where you thought it was does not announce itself; it turns up in a quarterly stocktake, by which time you have poured another eleven weeks of it.

That delay is the problem Super44 exists to shorten. It plugs into your POS and your Google reviews and surfaces the specific places profit is leaking in your venue, with the numbers attached and a short list of what to do about each one.

Super44 connects to your POS and shows you where your money leaks — then tells you what to do about it: https://super44.ai

## Where the pint figure comes from

The [Weights and Measures Act 1985](https://www.legislation.gov.uk/ukpga/1985/72/schedule/1) defines a pint as 0.568 261 25 of a litre and a gallon as 4.54609 litres. Everything else follows from those two numbers.

A 50-litre keg is 87.99 pints. A 30-litre keg is 52.79. The trade often calls a 50-litre keg an eleven-gallon, and that shorthand is sound: 11 imperial gallons is 50.007 litres, which is 88 pints almost exactly.

A cask is not the same size, and the names are where people come unstuck. A firkin is **nine** imperial gallons, which is 40.9 litres and 72 pints. Put 50 in the box for a firkin and you will understate your cost per pint by more than a fifth: a £75 firkin costs £1.04 a pint, not the 85p that 50 litres would suggest.

Cask is where this matters most, because a cask also loses volume to sediment that a keg does not, and the ullage at the end of a cask is real beer you paid for and cannot sell.

## Wastage is not a rounding error

Line cleaning is the big one. Every clean pulls the contents of the line to waste and then pulls beer through to refill it, and that happens on a schedule regardless of how much you sold that week. A long line on a slow-moving product can lose a startling proportion of the keg to a cleaning routine that is doing exactly what it should.

Which is why the wastage figure should be yours rather than ours. The 5% default in the calculator is there so the field is not empty. Your real number depends on line length, cleaning frequency, how many products you run and how fast each one moves.

It is also the reason a slow draught line can be quietly worse than break-even while every per-pint calculation on it looks healthy. The pints you sell carry the cost of the pints you poured away, and the fewer you sell, the more of that cost each one carries.

## The glass changes the answer

There is a second yield question sitting underneath the first, and it is the reason two pubs buying the same keg at the same price can honestly report different GPs.

A pint is a measure of liquid, but beer arrives with a head on it. [Aberdeenshire Council's Trading Standards team](https://www.aberdeenshire.gov.uk/news/2024/jul/don-t-lose-your-head-warn-trading-standards) put the industry position plainly in July 2024: **"Industry body the British Beer & Pub Association says a pint should contain a minimum of 95% liquid and 5% head."**

Do the arithmetic on that and it cuts both ways. Pour into a brim-measure glass, which has no fill line, and a pint with a head is about 0.95 pints of liquid, so a 50-litre keg stretches to roughly 92.6 servings rather than 88. Pour into a lined glass, where the line marks a full pint of liquid and the head sits above it, and you get your 88. That is a difference of about 5% of your servings on every keg, decided entirely by which glasses are on the shelf.

It is worth being clear about what that is and is not. It is an explanation for why your yield may look better or worse than the theoretical maximum. It is not a margin lever to reach for. The council's Protective Services Manager, Gordon Buchanan, framed the customer's side of it: **"Strictly speaking, a pint should mean a pint of liquid"**. Lined glasses cost you a few servings a keg and remove the argument entirely, which is a trade most operators would make.

## What the tie does to the number

Before you judge your GP against anything, check whether the comparison was ever about you.

UKHospitality and Christie & Co, working from members' actual profit and loss accounts, found that **wet-sales gross profit margins ran at 68.9% for estates held mainly on commercial leases against 61.2% for those on mainly tied leases.** The report puts the gap at 7.8 percentage points, on the same beer. It also asks for caution on that particular split, because its tied-lease sample is small, so treat it as the shape of the effect rather than a precise measure of it.

That is not a performance gap, it is the tie doing what a tie does: the landlord takes wholesale profit on the stock you are obliged to buy from them, usually in exchange for lower rent. If you are a tied tenant measuring yourself against a 65% draught figure you read on a wholesaler's website, you will conclude you are running a bad pub. You may just be running a tied one.

## A note on the pint price

The [ONS RPI series](https://www.ons.gov.uk/economy/inflationandpriceindices/timeseries/czms/mm23) last recorded an average price of £4.83 for a pint of draught lager, in January 2025, and has published no observation since. The calculator uses it as a default because it is the last published figure rather than because it is current, and if you have seen £4.83 quoted as today's average, that is where it came from.

Use your own price. The point of the default is to have something in the box.

## The rest of the bar

Spirits and wine have the opposite problem: no wastage to speak of, but a cost per serve that moves with the measure you pour. The [drinks GP calculator](/blog/drinks-gp-calculator) handles that. For the plain sum on any single line, use the [GP calculator](/blog/gp-calculator), which also covers why the VAT comes off first and why no trade body publishes the GP band everyone quotes at you.

## FAQ

### How many pints are in a keg?

A 50-litre keg holds 87.99 pints and a 30-litre keg holds 52.79, because the Weights and Measures Act 1985 defines a pint as 0.56826125 of a litre. Those are the pints in the container, not the pints you can sell. Line cleaning, sediment, gas issues and pull-through all come off before the saleable figure.

### What wastage figure should I use for draught?

Use your own, measured over a few weeks, rather than an industry number. Your wastage depends on line length, how often you clean, how many products you run and how fast each one sells, and a slow line on a long run wastes far more than a fast one. The calculator defaults to 5% only so the box is not empty.

### Why is my draught GP worse than my bottled GP?

Usually because draught carries a wastage cost that bottles do not. A bottle either sells or sits in the fridge, while a keg loses beer to line cleaning and pull-through whether it sells or not. That is also why a slow-selling draught line can be worse than break-even while looking fine on a per-pint calculation.

### Does this include the cost of gas and line cleaning?

No. This is gross profit on the beer itself. Gas, cleaning chemicals, cooling and the labour to clean lines are real costs of running draught, but they sit below the GP line. If you want to compare draught against packaged fairly, take those into account separately rather than trying to push them into the GP percentage.

## Sources

1. [Weights and Measures Act 1985, Schedule 1](https://www.legislation.gov.uk/ukpga/1985/72/schedule/1) — Pint defined as 0.568 261 25 cubic decimetre (Sch. 1 Pt. IV); gallon as 4.54609 cubic decimetres (Sch. 1 Pt. VI)
2. [GOV.UK - VAT rates on different goods and services](https://www.gov.uk/vat-rates) — "The standard VAT rate is 20%"
3. [ONS - RPI: Ave price - Draught lager, per pint (series CZMS)](https://www.ons.gov.uk/economy/inflationandpriceindices/timeseries/czms/mm23) — Final observation £4.83, January 2025; page released 19 August 2026
4. [Aberdeenshire Council Trading Standards - "Don't lose your head"](https://www.aberdeenshire.gov.uk/news/2024/jul/don-t-lose-your-head-warn-trading-standards) — 11 July 2024; "Industry body the British Beer & Pub Association says a pint should contain a minimum of 95% liquid and 5% head"; quotes Gordon Buchanan, Protective Services Manager
5. [UKHospitality & Christie & Co Benchmarking Report 2022 (13th edition)](https://www.ukhospitality.org.uk/wp-content/uploads/2025/01/UKHospitality-Christie-Co-Benchmarking-Report-2022-FINAL-abridged.pdf) — Six months to 31 December 2021, 4,791 managed outlets; wet-sales GP margin 68.9% on mainly commercial leases against 61.2% on mainly tied leases