How to spot supplier price increases when pack sizes change

Compare supplier prices per kilogram, litre or item before deciding whether a delivery is cheaper. A case price only tells you what the case costs. It does not tell you whether the case still contains the same amount of the same product.

That distinction matters when a substitution arrives, a manufacturer reduces a pack size, or a supplier changes the way a product is invoiced. The person checking the delivery and the person approving the bill need to be working from the same product definition.

A cheaper case, a higher unit cost

Consider an illustrative kitchen purchase. Last month's case contained five 1 kg bags and cost £30. This month's case contains four 1 kg bags and costs £28.

The case is £2 cheaper. The ingredient is £1 per kg more expensive:

• Previous cost: £30 divided by 5 kg = £6 per kg.
• New cost: £28 divided by 4 kg = £7 per kg.
• Increase per kg: £1 divided by £6 = approximately 16.7%.

The kitchen has not changed its recipe or portions. Its purchase cost has still moved. Comparing the case totals alone would hide the movement.

Use one consistent tax basis for the comparison. Identify delivery charges and discounts separately so an invoice-level charge does not look like a change in ingredient price.

Start with the product you actually received

Write down the supplier product code, description, number of units in the pack and quantity in each unit. Where relevant, include whether the quantity is a drained weight, a gross weight or a usable portion count.

A 2 kg pack of a ready-to-use product is not automatically comparable with a 2 kg product that needs trimming. Price per kg is a useful first check, but the specification and usable yield decide whether the products perform the same job.

If the product has changed, preserve that distinction. Updating the old description to fit the new delivery can make the historical comparison look cleaner while hiding the substitution that caused the difference.

Separate a cost increase from a billing discrepancy

There are two questions to ask. Did the supplier charge what was agreed? And has the cost of this comparable product changed over time?

An invoice can match the latest agreement and still represent an increase from the previous month. Conversely, an invoice can match last week's price while differing from a new negotiated rate.

Keep the agreement or quotation alongside its effective date. Compare the invoice with that record, then use comparable purchase history to assess the trend. For an example of this distinction in software, Lightyear documents price checking against an agreed supplier price.

The outcome should be a recorded decision: accepted change, supplier query, corrected invoice or substitution review. An alert without an owner simply moves the uncertainty into another inbox.

Give the receiving team a short check

The team at the door can confirm what finance cannot see later: the product, quantity and condition that arrived. They do not need to investigate the entire purchasing history during service.

They do need to record a changed pack size or substitution against the delivery. Finance can then check the charge against the agreement, while the chef or purchasing owner decides whether the product remains suitable.

The broader purchasing controls are covered in five procurement failures that leak margin. This check focuses on the detail that can disappear between receiving and invoice approval.

Review the effect before changing the menu

Once the increase is confirmed, estimate its effect using the quantities you actually purchase or consume. A large percentage increase on a rarely used garnish may matter less than a small increase on the ingredient you buy every day.

Review portions, waste, specification and supplier options before treating a menu price increase as the only response. Keep the stock position in the calculation: purchase expenditure alone is not the cost of what you sold. Our restaurant GP calculation guide explains the difference.

The useful result is a defensible decision made while the evidence is available. Hops Finance brings invoice and purchasing information into the operational workflow. If pack-size changes currently disappear between your delivery notes and accounts, arrange a demo around that workflow.