In the same unit. Catches the case where the big pack goes to waste.
Cheaper per unit is not always the better buy. Factor in shelf life, storage space and whether you will realistically get through it.
Calculated entirely in your browser. Nothing you enter is sent anywhere.
How to use it
Enter both prices and sizes
Use the same unit for both. Convert first if one is in pounds and the other in ounces.
Add what you will use
This is the field that catches the case where the big pack goes to waste.
Read both verdicts
Cheapest per unit and cheapest per unit actually used are not always the same option.
How the calculation works
The basic comparison is price divided by quantity for each option. Doing that in your head while standing in an aisle is where it falls apart, which is why unit pricing exists on shelf labels at all.
The waste calculation is the part that is usually missing. If you will use eighteen ounces and the bulk pack holds twenty-four, the real cost per ounce used is the full pack price divided by eighteen, not by twenty-four.
That single adjustment flips the answer surprisingly often, particularly for anything perishable.
What this calculator does not do
It does not know whether the larger pack will spoil before you finish it. The waste field is your judgement, not a measurement.
It does not convert between units. Both entries must be in the same unit or the comparison is meaningless.
It does not account for storage space or the cash tied up in buying ahead. Both are real costs a unit price cannot capture.
Questions
Why not just buy the bigger pack?
Usually it is cheaper per unit, but promotions on smaller sizes flip it more often than people expect, and shelf labels do not always show unit price.
What unit should I use?
Whichever the packaging uses, as long as both match. Ounces for dry goods, fluid ounces or litres for liquids, count for items.
Does this work beyond groceries?
Yes. Printer ink, cleaning products, pet food, building materials — anything sold in multiple pack sizes.
Should I always pick the lower unit price?
No. Half a cheap bulk pack in the bin costs more than a full expensive small one.
Related calculators
Cost Per Wear Calculator
True cost of a purchase over its life.
LIVEMulch Calculator
Bags or cubic yards for a bed.
LIVEInvoice Discount Calculator
Is early payment worth the discount?
LIVESomething wrong with this calculator? Report it and it gets fixed or taken down.
