How to Calculate GP in Your Pub
Last updated: 26 June 2026
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Most pubs don’t actually know their real GP until they get hit with a loss they didn’t see coming. You think you’re running 65% GP on spirits, but what you’re really tracking is a spreadsheet that never gets reconciled against actual stock. The difference between what you think you’re making and what you’re actually making — that gap is where thousands of pounds disappear every year.
If you’ve just taken on a pub, inherited a broken stocktake system, or realised your numbers don’t match your till, you’re not alone. Most licensees spend more time worrying about whether their GP is right than actually understanding how to calculate it properly. And that costs money.
This guide walks you through exactly how to calculate GP in your pub, what numbers actually matter, and how a simple weekly count routine can recover 1-2 GP points within a couple of months — money that’s already yours, just being lost to measurement error and forgotten waste.
You’ll learn the real formula, the specific steps to run a count that sticks, and why your spreadsheet probably isn’t catching the leaks that matter.
Key Takeaways
- GP is calculated as (Sales minus Cost of Goods Sold) divided by Sales, multiplied by 100 — but the number that matters is wet GP by line, not a single headline figure.
- A 1% loss on wet sales costs a typical pub £3,000–£5,000 a year, and most of it is measurement error, over-pouring, and forgotten waste — not theft.
- Weekly line checks with a dipstick, scales, and same-day till reconciliation catch losses in real time and usually recover 1-2 GP points within a couple of months.
- Spirits hide losses in over-pouring (a free-poured 25ml is often 32–35ml), draught hides it in poor cellar temperature and line cleaning waste, and partial kegs are the biggest reconciliation nightmare.
What GP Actually Means in a Pub
GP is the money left over after you pay for every bottle, pint, and cask that you sell — before overheads like labour, rent, or utilities. It’s expressed as a percentage. If your wet sales (draught beer, lager, cider, spirits, mixers, soft drinks) are £10,000 a week and your cost of goods sold is £3,500, your GP is 65%.
Most pub operators talk about “running 65% GP” or “hitting 68% GP”, but here’s the part nobody tells you: that number is almost always a guess. It’s based on opening stock plus purchases minus closing stock — a calculation that only works if your opening stock is accurate. And in most pubs, the opening stock is whatever the previous count said it was, which was probably guesswork too.
The number that actually matters is wet GP by line, not a single headline stock figure. Spirits, draught, bottled beers, soft drinks — they all have different usage patterns, different waste profiles, and different loss points. Spirits hide losses in over-pouring (a free-poured 25ml is often 32–35ml). Draught hides it in poor cellar temperature, bad line cleaning, and partial kegs sat in the corner that nobody’s counted in three months. Soft drinks hides it in spillage and untracked bottle swaps.
Until you can answer “what’s my draught GP this week?” and “what’s my spirit GP this week?” with a number you’ve actually verified against till data that same day, you’re not really calculating GP — you’re making an assumption.
How to Calculate GP: The Formula
The formula itself is simple:
GP% = (Sales – COGS) ÷ Sales × 100
Where COGS (Cost of Goods Sold) = Opening Stock + Purchases – Closing Stock.
But here’s where it breaks down in real pubs. You need three accurate numbers to make this work:
- Opening stock value: The cost price of every bottle, cask, and partial keg in your cellar at the start of the period (usually a week).
- Purchases: The cost of everything you’ve bought from your supplier in that period (your invoices).
- Closing stock value: The cost price of every bottle, cask, and partial keg in your cellar at the end of the period — and this is where most pubs fail.
Most closing stock counts are done by walking into the cellar, eyeballing a cask, writing down “1 Carlsberg keg”, and moving on. That’s not a count. That’s a inventory fiction. A proper closing stock count requires a dipstick (to measure cask fill), scales (to weigh open bottles), and a written record matched against your previous count, not guesswork.
Once you’ve got those three numbers, the COGS is straightforward. Then sales is just your till tape (or EPOS data) for the same period. Subtract, divide, multiply by 100, and you have your GP%.
The real GP calculation you should be running is: (Sales – Actual Stock Used) ÷ Sales × 100. And “actual stock used” means stock you’ve physically counted and reconciled against what you actually sold through the till.
Running a Proper Weekly Count
I’ve been running my own pub for 15 years, and I spent the first five of them on a tangle of spreadsheets and still losing track of partial kegs and spirit measures. Then I built a simple routine: a dipstick, a set of scales, a notepad, and one dedicated 90 minutes on a Tuesday morning when trade is light. Within a fortnight, my weekly variance went from what I’d describe as “pure guesswork” to a number I could actually trust.
Here’s exactly how it works:
Step 1: Count Draught at the Same Time Each Week
Use a dipstick to measure the fill level on every cask and partial keg in your cellar. Record the measurement against the product name and cask number. Do this at the same time each week (I do Tuesday morning) so your count window is consistent. A cask that reads “half full” on Tuesday should sell roughly the same amount of product by next Tuesday if your draught usage is stable.
The dipstick method works because it removes the guesswork. You’re not eyeballing. You’re measuring. A standard 9-gallon cask holds 40.9 litres. A Guinness cask holds 29.1 litres. If your dipstick reads “60% full”, you’ve got 60% of that volume still in the cellar.
Step 2: Weigh Every Open Spirit Bottle
Spirits are where most pubs lose money, and they lose it through over-pouring, not theft. A free-poured 25ml measure is frequently 32–35ml. A “regular” customer who gets 35ml instead of 25ml four times a week is costing you approximately £80 a year just from that single customer. Multiply that by every bar person pouring by eye, and you can see where the 1% loss comes from.
Use digital scales to weigh every open spirit bottle once a week. Record the weight. The following week, subtract the new weight from the previous week’s weight, divide by the alcohol density of the spirit (roughly 0.789 g/ml for 40% ABV), and you’ve got your actual usage. Compare it against your till data. If you sold 30 measures of Jägermeister but the scales say you used the equivalent of 45 measures, you’ve found your leak.
Step 3: Match Everything Against Till Data the Same Day
Don’t wait until Friday to reconcile your Wednesday count. Do it the same day, or the next morning at the latest. Pull your EPOS data (or till tape) for the exact period — say, Tuesday 09:00 to Tuesday 08:59 the following week — and compare:
- Carlsberg sold (from till) versus Carlsberg used (from dipstick).
- Vodka sold (from till) versus vodka used (from scales).
- Guinness sold (from till) versus Guinness used (from dipstick).
The variance should be tiny — maybe 1–2%. If it’s 5% or more, you’ve either got a pour measure problem, a till input error, or an untracked waste event (like a split pint or a training error). Finding it the same week is the only way to fix it while the evidence is fresh.
Step 4: Document Waste Events in Real Time
Keep a waste book in your cellar. Every time something gets spilled, a line gets cleaned, a training measure pours, or a cask is changed, write it down with the date, time, product, and rough volume. This is the reconciliation cushion. If your till says you sold 50 pints of Heineken but your dip says 51.2 pints were used, your waste book might show a line clean (0.5 pint) and a training pour (0.7 pints), and your numbers are now aligned.
Without a waste book, every untracked event becomes “missing stock” in your mind, even though it’s not lost — it’s just unaccounted for.
Common Mistakes That Hide Losses
I’ve seen every version of this gone wrong, usually because licensees are trying to save time.
Mistake 1: Counting Stock Once a Month
Monthly counts are too slow to catch leaks. By the time you realise there’s a 5% variance on spirits, four weeks of over-pouring have already happened. Weekly counts, run on the same day, allow you to spot a problem within 7 days and address it (retraining, till adjustment, or genuinely finding a leak) before it compounds.
Mistake 2: Not Weighing Open Bottles
If you’re estimating spirit usage by counting how many bottles are empty, you’ve already lost the game. Empty bottles tell you nothing about how much poured out of each one. A 70cl bottle of Vodka that’s 10% full still has 630ml in it. If you’ve sold 20 measures (500ml at 25ml per measure) but didn’t weigh the bottle, you might think you’ve only got 130ml unaccounted for when you actually have 630ml, suggesting 5.2 measures of waste or loss when you really only have 0.52.
Mistake 3: Eyeballing Cask Fill
A cask that looks “half full” might be 45% full or 55% full. Over a month, that margin of error stacks. A dipstick costs £12. Use it.
Mistake 4: Not Matching Till Data to the Same Time Window
Your count runs Tuesday 09:00 to Tuesday 09:00 the following week. Your till data should run the exact same window. If you’re comparing Tuesday 00:00 to Tuesday 23:59 against a count that ran Tuesday 09:00 to Tuesday 09:00, you’ve built a 9-hour mismatch into your reconciliation that will create phantom variances.
Mistake 5: Assuming the Brewery Stocktaker Does It
Most pubcos send a stocktaker around every four weeks or monthly. But that stocktaker is working to their schedule, not yours. They’re counting for their records and their GP, not your GP. They might be eyeballing. They’re definitely not running same-day till reconciliation. And they’re not running weekly. Treat their count as a spot check and audit, not your primary control.
What Equipment You Actually Need
The myth: proper stocktaking requires expensive software and complex kit. The reality: you need about £40 of equipment and discipline.
- Dipstick (£12): Plastic rod with depth markings. Accurate to within 0.5 litres on a standard cask. Buy one per cask size you stock.
- Digital scales (£20–£30): 5kg capacity, ±1g accuracy. Enough for bottles up to 5kg. Tare function essential.
- Notebook (£2): Paper is faster than entering data into your phone during a count. You can photograph pages and file them later.
- Till or EPOS access (free): Most modern systems let you export sales data by product and time window. Use it.
- StockTap pub stock app (optional, £97 one-off): If you want a structured digital log instead of a notebook — one-time cost, no subscription. StockTap pub stock app is built by a working pub landlord and handles cask dips, bottle weights, waste notes, and variance alerts in one place.
Do you need the app? Honestly, no. But if you’re running multiple lines and want a searchable history of your counts, variance trends, and product-by-product GP, it takes the friction out of keeping records. The cost of one cask of beer pays for a year of better stock discipline.
How to Reconcile Stock Against Till Data
The most effective way to reconcile stock is to compare your physical count of what left the cellar against your till record of what was sold, on the same day, for the same time window.
Here’s a worked example from my own pub, Tuesday morning count:
Carlsberg Draught:
- Till says sold: 42 pints
- Cask dip says used: 40.8 litres (42.6 pints, accounting for pour waste)
- Waste book shows: line clean (0.6 pint)
- Variance: +0.8 pints (acceptable, within normal range)
Vodka:
- Till says sold: 18 measures
- Bottle weight shows used: 450ml (18 × 25ml = 450ml, exactly on target)
- Waste book shows: 0
- Variance: 0% (perfect)
Guinness:
- Till says sold: 51 pints
- Cask dip says used: 47.2 litres (50.3 pints)
- Waste book shows: training pour (0.7 pint)
- Variance: –1% (suggests a till entry error or a measure slightly short)
That kind of line-by-line reconciliation is what separates “I think I’m at 65% GP” from “I know I’m at 65.3% GP and I know where the 0.7 pint variance came from”.
Once you’ve got three weeks of good data, you can spot patterns. If Carlsberg is consistently running 2–3% over every week, you’ve got a pour measure issue or untrained staff. If Vodka is spot-on but Gin is 4% under, you’ve found where the losses are hiding. That information is worth thousands in recovery.
Most pubs that move from a messy spreadsheet to a disciplined weekly count and same-day reconciliation routine claw back 1–2 GP points within a couple of months. That’s real money. A typical pub running £15,000 a week in wet sales will recover £2,250–£4,500 in the first 60 days.
Frequently Asked Questions
How often should I calculate GP in my pub?
Weekly. Monthly is too slow to catch leaks. Run your count on the same day each week (I use Tuesday), reconcile against till data the same day, and you’ll spot a variance within 7 days instead of 30. This allows you to fix a problem (retraining, till error, or actual loss) before it compounds across four weeks.
What’s a normal GP% for a pub?
Most UK pubs run 60–70% GP on wet sales. Spirits typically sit at 65–72%, draught at 58–65%, and soft drinks at 70–78%. But your target should be based on your own baseline and your supplier agreements, not on what the pub down the road is doing. What matters is consistency week to week — if you hit 66% one week and 62% the next, something changed, and you need to find out what.
What’s the difference between GP and net profit?
GP is revenue minus cost of goods sold — the money left after you pay for stock. Net profit is what’s left after you also pay labour, rent, rates, utilities, insurance, and everything else. You can have high GP and low net profit if your overheads are sky-high. GP is your stock efficiency. Net profit is whether your pub actually makes money.
Can I calculate GP if I don’t have an EPOS system?
Yes, but it’s harder. You’ll need accurate till rolls and manual notes of every product sold. A hand-written till system is slower and more error-prone than EPOS, but the reconciliation method stays the same: physical stock out minus waste events should equal till sales. If you’re still using a cash register and paper rolls, upgrading to even a basic EPOS (iPad-based systems start at £300–£500) will cut your reconciliation time in half and eliminate till entry errors.
Why do my numbers never match exactly?
Because no pub ever uses stock with perfect 100% accuracy. There are always small variances: a measure poured slightly heavy, a line cleaned with product still in it, a training pour, a broken glass, a partial keg left sitting untracked for three days. A variance of 1–2% is normal and acceptable. If you’re running 5%+ variance, you’ve got a systemic problem — usually over-pouring, an untrained team, or a till error. A waste book documents these small events so you can explain them instead of treating them as mystery losses.
Tracking stock manually takes time — time most pub licensees don’t have. And a spreadsheet makes it easy to miss partial kegs, forget what you counted last week, or reconcile till data days after the count when the numbers have moved on.
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