Unit Price Comparison
Whether a bigger pack is really cheaper, by comparing the price per unit.
Enter your numbers
Formula
How the calculation works
Comparing packs by their total price is misleading, because a bigger pack costs more by definition. What decides value is the price per unit of the thing itself: the total divided by the quantity. Twelve for 120 is 10 each; twenty-four for 200 is 8.33 each. The second pack costs more money and less per unit, and only the per-unit figure shows that.
When two packs are given, the tool reports the saving as a percentage of the dearer per-unit figure, not as a ratio between the two. That is the number a shopper actually wants, because it answers how much cheaper the better pack is rather than how the two relate. On the example above the saving is about 16.7%, which is what you gain by choosing the second pack.
The comparison only holds when both quantities measure the same thing in the same unit. Per gram against per gram is meaningful; per gram against per item is not, and neither is a pack measured in pieces against one measured by weight.
Common mistakes
- Comparing the two total prices. The larger pack almost always costs more overall, which says nothing about value.
- Assuming a bigger pack is cheaper per unit. It sometimes is not, which is exactly what this tool is for.
- Comparing packs measured in different units, such as a price per gram against a price per item, which produces a meaningless result.
When to use it
- Use it in the shop when two packs of the same product are in front of you and the labels make it hard to tell which is better value.
- It is a comparison of two packs, not a full price tracker. For a basket of many items, or for packs of genuinely different products, it will not help.
Worked example
12 for 120 is 10 each; 24 for 200 is 8.33 each, so the second is 16.67% cheaper.
Common questions
Is the bigger pack always cheaper?
No. Larger packs are sometimes priced higher per unit, because people assume bigger means cheaper. This catches that.
Related tools
-
Discount Calculator
See what you actually pay after a discount, and how much you save.
-
Tip Calculator
Add a tip to the bill and split it between people.
-
Add Tax / VAT Calculator
Add tax or VAT to a price to get the total.
-
Percentage Calculator
Find what percentage one number is of another.
-
Percentage Change
How much a number rose or fell between two points.
-
Monthly Budget Split
Divide monthly income into needs, wants and savings.