Multipack
Product A: 6 rolls × 160 sheets for $3.95
Product B: 8 rolls × 120 sheets for $4.20
The calculator uses the total quantity from item count × content per item.
Unit Price Calculator for Packages, Quantities and Prices
Compare two packages on the same basis and see which offer is really cheaper, even when sizes, quantities or multipacks differ.
Compare packages and prices directly
Enter the price, quantity and, when needed, the content per item for both products. The calculator puts both packages on the same comparison basis and shows which offer is cheaper.
How to fill in the calculator
Copy the price and quantity from each package.
Use the same kind of quantity for both products.
Compare grams with grams, liters with liters and items with items.
Product A
Product B
Why package prices can be misleading
Two packages can have similar shelf prices but contain different amounts. The package price alone therefore says little; the unit price puts every package on the same basis.
Less content at the same price
Old package
- Package size
- 500 g
- Shelf price
- $3.99
- Price per kg
- $7.98
11.11% higher unit price
New package
- Package size
- 450 g
- Shelf price
- $3.99
- Price per kg
- $8.87
What is shrinkflation?
When the quantity falls while the price stays the same, the price per kilogram rises, here by about 11%. This is called shrinkflation. Comparing unit prices makes such hidden increases visible.
Comparing prices correctly
A low package price does not mean a low price for the amount you get. These points help you compare offers on a common basis.
How to read the unit price
The unit price is what a product costs per fixed quantity, such as per kilogram, liter or item. It puts packages of different sizes on the same basis. In the United States, unit pricing is not required by federal law; whether a store has to show it depends on the state, and many stores show it on the shelf label.
Always compare the same reference quantity: a price per kilogram cannot be compared directly with a price per 100 g without converting one of them.
Unit price = price ÷ quantity
Example: $3.99 for 500 g → $3.99 ÷ 0.5 kg = $7.98 per kg.
Skimpflation: same amount, changed recipe
Not every hidden change affects the package size. With skimpflation the amount stays the same while the recipe changes, for example when cheaper ingredients replace more expensive ones.
A unit price cannot judge quality or recipe changes. If a product has changed, also check the ingredient list and the product description.
Check XXL, family and value packs
Labels such as XXL, family pack or value pack do not mean the larger package is cheaper per unit. What counts is the price on the same quantity basis.
Compare the price per kilogram, liter, item or another sensible common unit, not just the price or size of the package.
Compare multipacks
For multipacks, the number of units alone is often misleading; the total amount matters. Multiply the number of units by the content per unit.
Example: 6 rolls × 160 sheets = 960 sheets, and 8 rolls × 120 sheets = 960 sheets. Only on this common basis can you tell which package is cheaper.
Put discounts and special offers in context
A striking discount does not show whether an offer is cheap compared with another package size. What counts is the price you actually pay in relation to the amount you get.
Compare the resulting price on the same quantity basis, even for special offers. A percentage discount can be useful, but it does not replace the direct quantity comparison.
When the larger package is still not the better choice
A lower price per kilogram or liter does not automatically make the larger package the better purchase. If part of the product goes unused, spoils or is hard to store, a smaller package can be the more practical choice despite the higher unit price.
The calculator only compares price relative to the amount you enter. It does not consider quality, shelf life, your own consumption or storage.
Common comparison situations
Package prices alone often say little. These examples show which basis matters for a fair comparison.
Compare price per use
- Product A: 1.4 L of liquid laundry detergent for $3.95 · 28 washes
- Product B: 1.8 L of liquid laundry detergent for $5.20 · 36 washes
Do not compare only the price per liter. For laundry detergent, the price per wash can also show which offer is genuinely cheaper.
Check a larger package
- Product A: 750 g of coffee for $6.49
- Product B: 1 kg of coffee for $8.99
A larger package is not automatically cheaper. The price per kilogram makes the two offers directly comparable.
Frequently asked questions
What does unit price mean?
Unit price is the price for a fixed comparison quantity, such as one kilogram, one liter, 100 g, 100 ml, or one item.
Is the larger package always cheaper?
No. A larger package can still have a higher unit price. Compare both offers on the same quantity basis.
How do I spot less content at the same price?
Compare the old and new package sizes at the same or a similar price. If the unit price rises, you are paying more for the quantity.
Can I compare prices per item?
Yes. Enter each package price and item count as the quantity. The lower result is cheaper per item.
What is shrinkflation?
Shrinkflation means a package contains less while the price stays the same or rises, so the price per unit goes up.
What is skimpflation?
With skimpflation the amount stays the same while the recipe or ingredients change. A price and quantity comparison cannot judge such quality changes.
Sources and background
The notes on unit pricing and shrinkflation are based on these US government sources.