Actual vs Theoretical GP Calculator
Compare actual GP against theoretical GP after stocktake. Spot unexplained variance, waste, over-portioning, comps and margin leakage - and see the annualised cost if it continues.
Target vs theoretical vs actual GP
Variance can come from over-portioning, incorrect recipes, unrecorded waste, supplier price changes, complimentary items, stock-counting errors, unrecorded staff consumption or stock loss.
Save these numbers before you close the tab
Email yourself a copy, save it for later, or print a branded summary to share with your team or accountant.
Branded A4 PDF · saved costings sync across all your devices.
What to work out next
All calculators →About this calculator
Actual GP is what your stocktake proves you made. Theoretical GP is what your recipes and till say you should have made. When the two drift apart, money is leaking somewhere between purchase and till.
Formula: Actual COS = Opening + Purchases + Transfers in − Closing − Transfers out. Actual GP % = (Net sales − Actual COS) ÷ Net sales × 100. Variance = Actual GP % − Theoretical GP %.
Use it after every stocktake. A 1–2 point variance is normal noise; anything larger points to portioning, recipe accuracy, unrecorded waste, comps, supplier price changes or stock loss.
What this calculator does
Compares the GP your recipes say you should achieve with the GP your stocktake actually delivered, quantifies the gap in pounds, and projects what the leakage costs across a year.
Who it is for
- Operators who stocktake and want the variance turned into money.
- Bar and kitchen managers investigating a GP drop.
- Finance teams reconciling the P&L against recipe costings.
How to use it
- Enter opening stock, purchases and closing stock for the period to derive cost of sales.
- Enter net sales for the same period.
- Enter your theoretical GP percentage from your recipe costings.
- Read the actual GP, the variance in percentage points and the cash value of the gap.
The formula
- Cost of sales = Opening stock + Purchases - Closing stock
- Actual GP% = ((Net sales - Cost of sales) / Net sales) x 100
- Variance in points = Theoretical GP% - Actual GP%
- Cash variance = Net sales x (Variance in points / 100)
Worked example
A period with £42,000 net sales, £9,400 opening stock, £11,800 purchases and £8,900 closing stock, against a theoretical GP of 73.5%.
- Cost of sales = £9,400 + £11,800 - £8,900 = £12,300
- Actual GP = (£42,000 - £12,300) / £42,000 = 70.7%
- Variance = 73.5% - 70.7% = 2.8 percentage points
- Cash variance = £42,000 x 2.8% = £1,176 per period, or £15,288 across 13 periods
2.8 points of unexplained GP leakage, worth £1,176 a period and over £15,000 a year.
How to read your result
- A variance of a point or so is normal noise. A persistent gap of several points is a process problem, not bad luck.
- The usual causes, in rough order of frequency: over-portioning and free pouring, unlogged waste, comps and staff drinks, delivery and invoice errors, then theft.
- If actual GP is higher than theoretical, your recipes are probably out of date rather than your bar being unusually efficient.
What to do next
- Split the variance by category - wet and dry behave completely differently.
- Re-cost the top twenty selling lines before blaming the team; stale recipe costs create phantom variance.
- Log waste and comps properly for four weeks and see how much of the gap becomes explained.
Common mistakes to avoid
- Comparing an actual GP that includes VAT-inclusive sales with a theoretical GP built on net prices.
- Inconsistent stocktake timing or valuation between periods, which invents variance that is not there.
- Not counting stock held in prep, cellar or off-site.
Assumptions and limitations
- Accuracy depends entirely on stocktake discipline; a rushed count makes the whole comparison meaningless.
- The annualised figure assumes the variance persists, which is a projection rather than a forecast.
Dumb Bambi provides general business information, not accounting, tax or legal advice. Read our calculation methodology or tell us about a mistake.
Last reviewed:
Keep going with these tools
- GP Calculator - Gross profit, GP % and markup % in one place.
- Food Waste & Stock Loss Calculator - Waste %, projected annual cost and savings at your target.
- Menu Engineering Calculator - Classify dishes as Star, Ploughhorse, Puzzle or Dog.
Frequently asked questions
What is a healthy GP variance?+
Under 1 percentage point is well controlled. 1–2 points is normal for a busy operation. Above 3 points is worth a proper investigation.
Why is my actual GP lower than theoretical?+
The usual suspects are over-portioning, incorrect recipes on the till, unrecorded waste, missed comps and staff drinks, supplier price rises since the recipe was costed, and stock-count errors.
How often should I stocktake?+
Weekly for wet stock, monthly for food. The more frequent the count, the smaller the variance you can act on.
Does this replace an EPOS stock module?+
No - it's a fast operator view. If your EPOS gives you both numbers, use this to interpret them and drive action.