A supplier’s new price can look cheaper because the pack price fell, while each kilogram costs more. Comparing pack prices across a pack-size change hides that movement, and averaging outlets together can blur it again.
This guide compares one supplier’s price for one approved item at two dates, per base unit and separately for each outlet. It uses pack conversions already approved in the item master and does not calculate spend, savings or yield. PC-029 is an original fictional example.
Fix the item, supplier and price basis
Name the supplier, the canonical item with its specification revision and the base unit. In PC-029 the supplier is S1, the item is COF-29, roasted coffee beans to specification R1, and the base unit is the net kilogram declared on the pack. That is a purchase quantity, not the usable yield after preparation.
Both prices must sit on the same basis. Here every figure is in INR for net merchandise, excluding tax and delivery, on the same documented discount basis. This guide makes no claim about tax recovery. If one price includes delivery and the other does not, stop until the basis is resolved. Record the price list, quotation or invoice behind each figure and its date.
Take pack factors from approved mappings
Use the pack mappings already approved in the item master, not a factor read from a label in the moment. PK5 holds 5 kg and PK4 holds 4 kg. Evidence MAP29 confirms that both packs contain the same item to specification R1, and that only the pack size changed. Because that equivalence is approved, both packs stay under COF-29.
A pack-size change alone need not create a new item. A different blend, formula or concentration is not automatically comparable, however similar the name. If the equivalence evidence is unresolved, there is no comparable price change to report yet.
Worked example: PC-029, 1 October to 1 November 2026
Each outlet buys under its own dated price, so each gets its own comparison. All figures are INR, net merchandise, excluding tax and delivery.
| Outlet | Earlier price, 1 Oct 2026 | Later price, 1 Nov 2026 | Change per kg | Pack price change |
|---|---|---|---|---|
| North | PK5 at 600 = 120 per kg | PK4 at 520 = 130 per kg | +10 per kg (8.3%) | Fell 13.3% |
| South | PK5 at 625 = 125 per kg | PK4 at 540 = 135 per kg | +10 per kg (8.0%) | Fell 13.6% |
Read the unit price, not the pack price
At North, INR 600 ÷ 5 = INR 120 per kg became INR 520 ÷ 4 = INR 130 per kg. The increase is INR 10 per kg, or 10 ÷ 120 = 8.333%, shown as 8.3%. The pack price fell by 13.3% at the same time, which is why reading pack prices alone points the wrong way.
At South, INR 125 per kg became INR 135, the same INR 10 increase but 8.0% because the earlier price was higher. Keep the two results side by side. Do not average 8.3% and 8.0% into a group figure; each describes one outlet’s price basis. If an earlier unit price were zero, the absolute change could be stated but a percentage could not.
A price change is not a spend change
PC-029 records no quantities purchased, so it says nothing about what either outlet spent, saved or will spend. Buying fewer kilograms at the higher price could lower spend; buying the same amount would raise it. Describe any spend or usage effect separately rather than deriving it from this comparison.
Do not label the result inflation or a saving. Prices move for many reasons, and two dated prices from one supplier cannot separate them.
Keep proposals, terms and implementation separate
A supplier’s price proposal, the effective terms agreed and the purchasing change approved for the outlets are separate decisions. Record which document each price comes from, its date and who reviewed it, and keep both dated prices with their evidence rather than overwriting the earlier one.
This comparison informs those decisions. It does not approve a supplier, a price or an item master update. Comparing one supplier with another for the same item is a different exercise.
What the purchasing source supports
The BCcampus purchasing chapter describes specifications that include packaging size, net or drained quantity where relevant, and count per case. It also discusses changing food prices and comparable quality. Those general purchasing principles support preserving the item specification and the dated price evidence. The conversions and calculations here are original; the source’s foreign specification tables, example figures and recommended quotation counts are not adopted.
Put it into practice
Your action checklist
Your progress saves in this browser. No sign-up needed.
0 of 9 complete
From reading to doing
Supplier Price Change
Open Supplier Price Change to compare one supplier's price for one item at two dates. The sheet has two independent, reusable comparison slots, shown with the North and South example. Typed fields cover the comparison ID, outlet, supplier, item and specification, currency, base unit and common price basis. They also cover an equivalence decision of Confirmed or Unresolved with its evidence, the earlier and later dates, pack references, base units per pack, pack prices and price evidence. Formulas calculate the price per base unit at each date, the absolute change, the unit-price percentage change and the pack-price percentage change. Both dates are required, with the later date after the earlier one. Pack factors must be positive and prices non-negative. A zero earlier unit price allows the absolute change but shows the percentage as not available. Missing required inputs or an Unresolved equivalence suppress the result. Duplicate slot IDs are flagged for Review. The two slots are never combined into a group figure. There are 6 manual review and action rows. Copy the sheet for further comparisons. It does not update the item master or approve purchasing.
Open the Supplier Price Change tab in the launch workbook. Keep a copy for your own business.
Download the free workbook See what’s inside the toolkit →Sources & further reading
- Purchasing, Basic Kitchen and Food Service Management (opentextbc.ca) ↗
BC Cook Articulation Committee, 2015; retrieved 8 November 2026. Used for general purchasing principles: comparable specifications, package quantities, changing prices and documented price/case information. No foreign specifications, example prices or quotation-count rule is adopted. PC-029 and its arithmetic are original illustrations.
Published by Keystonne Grow. Product links connect to the Keystonne ecosystem; check the linked product or service for its current scope.