How to compare supplier prices when pack sizes differ
The cheapest case is often the most expensive gram. Convert every quote to one usage unit, then correct for yield, and the ranking frequently reverses.
Convert every quote to the same usage unit before comparing anything, then correct each one for yield. A bigger pack is not automatically cheaper, and the quote that looks best per case is regularly the worst per gram.
Cost per usage unit = pack price divided by pack quantity converted to your usage unit
Worked example: three olive oil quotes
- Supplier A: 5 L tin at $41.00, so $41.00 divided by 5,000 ml = $0.0082/ml
- Supplier B: 3 L tin at $23.40, so $23.40 divided by 3,000 ml = $0.0078/ml
- Supplier C: 12 x 1 L case at $102.00, so $102.00 divided by 12,000 ml = $0.0085/ml
The smallest pack wins and the largest loses, which is the opposite of the assumption most kitchens buy on. At 50 liters a month, choosing B over C is $35 a month on one ingredient, or $420 a year.
Then correct for yield, which can reverse it again
Unit price is what you paid. Cost per usable unit is what reaches the plate, and on anything you trim they are different numbers.
- Supplier A: chicken at $9.50/kg, 88% usable after trim, so $9.50 divided by 0.88 = $10.80 per usable kg
- Supplier B: chicken at $8.90/kg, 78% usable, so $8.90 divided by 0.78 = $11.41 per usable kg
The cheaper chicken costs 5.7% more on the plate. This is the single most common way a kitchen negotiates itself into a worse price, because the invoice genuinely does show a lower number.
Cost per usable unit = pack price divided by (pack quantity x usable yield)
Ask for a sample before switching a high-volume protein, break it down yourself, and weigh what is left.
What else changes the real price
- Pack size against your actual usage rate. A 5 L tin is cheaper per ml and worthless if the oil oxidizes before you finish it. Buy the pack you will use inside its life, not the one with the best headline rate.
- Minimum order value. A better unit price behind a $400 minimum is a storage and cash-flow decision, not just a price.
- Delivery frequency. Two deliveries a week instead of one is less stock on hand, less spoilage, and less capital sitting in a walk-in.
- Consistency. A supplier whose trim varies week to week makes every cost you store slightly wrong, which is worth more than a few cents a kilo.
Re-quote on a schedule, not on a hunch
Prices move and quotes go stale quietly. Re-quote your top ten ingredients by spend once or twice a year. Those ten are usually most of your food cost, and the rest is not worth the phone calls.
Frequently asked questions
- Should I move all my volume to the cheapest supplier?
- Rarely. A second supplier on your highest-spend items is worth the small premium, because a single source turns one delivery failure into a menu you cannot serve.
- How do I compare a quote in pounds against one in kilograms?
- Convert both to the unit your recipes actually use before you look at either price. Comparing in the unit you buy in is what makes an unfamiliar pack size look cheap.
- Does a volume rebate change the comparison?
- Only if you would have bought that volume anyway. A rebate that requires 20% more stock than you use is a discount on waste.
- What if a supplier will not quote per unit?
- Work it out yourself from the pack price and pack size, and be a little wary. A quote that is hard to compare is sometimes hard to compare on purpose.
Enter each pack price and pack size and read the cost per usage unit side by side.
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