Friday Ready guide · costing and purchasing
Restaurant supplier price changes: what to check before changing your menu
A higher invoice total does not tell you which dish needs attention. You may have bought more stock, received a smaller pack, lost a discount or accepted a substitute. Start by finding what changed, then trace it to the portions you actually sell.
This routine works for an independent restaurant, café or takeaway using a simple costing sheet. You need the previous price, the new price, the pack specification and the relevant recipe quantities.
By Friday Ready · Reviewed 11 October 2026
1. Compare the same product and buying unit
Check the product code, brand, pack weight or item count, and whether the quoted price is per pack, case or kilogram. Note delivery charges and discounts separately so you can see their effect rather than quietly mixing them into one ingredient price.
Use a consistent tax basis throughout the comparison. If you are unsure how to treat tax in your own costing records, confirm that basis with your accountant before using the figures for pricing.
For ingredients measured by weight:
Cost per kilogram = pack price ÷ pack weight in kilograms.
For items counted individually, use cost per item. A case of 80 wraps and a case of 100 wraps are different buying units, even if both appear as “one case” on an order sheet.
2. Check what is usable
A cheaper product may need more trimming or have a different drained weight. If the recipe uses cooked or drained quantities, check the yield on that same basis. Avoid comparing a raw purchase weight with a cooked serving weight without an appropriate measured conversion.
Record the assumption beside the price. If a supplier sends a replacement product, test the relevant yield and portion before treating it as equivalent.
3. Update the affected dishes
Create a short “used in” list for each changed ingredient. Include sauces, sides and garnishes; one product may appear in several recipes.
Ingredient cost per portion = cost per usable unit × quantity used per portion.
Update the recipe cost, then compare the old and new portion costs. Check the actual serving quantity as well as the written recipe. A precise ingredient price will not fix an inconsistent portion.
For help connecting ingredient inputs, portions and pricing comparisons, see restaurant menu costing support.
Invented worked example: a smaller cheese pack
This example is invented to demonstrate the calculation. It is not a client result or a savings claim. Assume the full pack is usable and all figures use the same tax basis.
| Input | Previous pack | New pack |
|---|---|---|
| Pack price | £18.00 | £19.20 |
| Pack weight | 2.00 kg | 1.60 kg |
| Cost per kg | £9.00 | £12.00 |
| Cheese used per toastie | 0.080 kg | 0.080 kg |
| Cheese cost per toastie | £0.72 | £0.96 |
The pack price increased by about 6.7%, but the cost per kilogram increased by about 33.3%. The cheese cost per toastie rose by £0.24. If 150 toasties use that portion, the ingredient-cost difference is £36. This is an arithmetic scenario, not a forecast or a net-profit calculation.
The owner still needs the rest of the recipe cost, selling costs, demand and market context before deciding what to change.
4. Choose a response and record it
Compare realistic options: retain the current offer, review the selling price, change the buying arrangement, trial a different ingredient or revise the recipe. A recipe or portion change should preserve the product customers expect and be communicated accurately.
For a substitute ingredient, check the current specification and allergen information before using it. The Food Standards Agency's guidance says allergen ingredient information should be current and account for recipe changes. Its cited guidance applies to England, Wales and Northern Ireland; use the relevant local authority guidance elsewhere. Official allergen guidance.
Give each approved change a date and an owner. Update the costing input, order specification and affected recipe records together. If pack sizes or counting units changed, also review your stock-control and ordering routine.
Start with the next changed invoice
Choose one changed ingredient. Compare its buying unit, calculate its current usable-unit cost, update the affected recipes and record the decision. Then repeat this check when prices or specifications change; choose a regular review interval that fits your operation.
If the issue is wider than one ingredient, the £150 Friday Test provides a written operational review and practical priorities. If you already know what needs building, ask about a scoped and quoted Friday Fix.