Plot No. 34 · Everyday & Shopping
Unit Price Comparison Calculator
Compare two products by price per unit to see which is really cheaper. It divides each product's price by its size, so a 2.50 pack of 500 costs 0.005 per unit and a 3.20 pack of 750 costs about 0.0043 per unit. The bigger pack wins here, saving about 14.7 percent per unit.
Product A
Product B
Use the same size unit for both products (for example grams, millilitres or count).
The link saves your inputs so you can bookmark or share this exact result.
How the unit price is worked out
This calculator divides each product's price by its size to give a price per unit, then compares the two. A 2.50 pack holding 500 units costs 0.005 per unit, while a 3.20 pack holding 750 units costs about 0.00427 per unit, so the larger pack is cheaper per unit.
It then tells you which product wins and the percentage you save per unit by choosing it. In the example above the bigger pack saves about 14.7 percent per unit. The size can be any measure you like, such as grams, millilitres, sheets or count, as long as both products use the same unit.
How to use the unit price calculator
- Enter the price and the size of the first product, using the size in grams, millilitres or count.
- Enter the price and size of the second product in the same size unit.
- Read which product is cheaper per unit and how much you save by picking it.
Worked examples
Two pack sizes
Inputs: Product A 2.50 for 500, Product B 3.20 for 750
Result: A is 0.005 per unit, B is about 0.00427 per unit, so B wins and saves about 14.7 percent per unit.
Small versus large bottle
Inputs: Product A 1.00 for 250 ml, Product B 1.60 for 500 ml
Result: A is 0.004 per ml, B is 0.0032 per ml, so the large bottle is cheaper and saves 20 percent per ml.
Limitations and common mistakes
Edge cases and limitations
- Both sizes must be in the same unit; comparing a price per gram against a price per millilitre is meaningless.
- The lowest unit price is not always the best buy if the larger pack spoils before you use it.
- It compares value per unit, not total spend, so the cheaper unit price may still cost more upfront.
Common mistakes
- Entering one size in grams and the other in kilograms, which makes the comparison wrong by a factor of a thousand.
- Assuming the bigger pack is automatically better value without checking the actual unit prices.
Frequently asked questions
How do I compare two products by price?
Divide each product's price by its size to get a price per unit, then compare those. A 2.50 product holding 500 units costs 0.005 each, while a 3.20 product holding 750 units costs about 0.00427 each, so the second is cheaper per unit.
What counts as the size to enter?
Use whatever unit the pack is measured in, such as grams, millilitres, sheets or count, and make sure both products use the same unit. Comparing a price per gram against a price per millilitre gives a meaningless answer.
Is the cheapest unit price always the best buy?
Usually for value, but not always in practice. A larger pack with the lower unit price can be a false economy if the product spoils before you use it, or if you do not have storage. Unit price tells you value per unit, not whether you will use it all.
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