Everyday Life
Unit Price Comparison Calculator
Bigger is not always cheaper. Compare the price per gram, litre or item of two packs to see which is the real bargain.
The result shows the price per kilogram or litre for each pack and names the cheaper pack.
Formula
Unit price = pack price / pack size. Compare the two unit prices.
How it works
Unit price cuts through packaging tricks: a large pack with a higher per-kilo price is not a deal, however big it looks.
Only buy the cheaper large pack if you will actually use it before it expires — waste wipes out the saving.
Worked example
For example, Pack A at $3.50 for 500 g costs $7.00 per kilogram, and Pack B at $4.20 for 750 g costs $5.60 per kilogram, so Pack B is cheaper.
FAQs
What unit should I compare?
Use the same unit for both packs — grams with grams, litres with litres — or convert to per kilo / per litre.
Why do shops show unit prices?
So shoppers can compare fairly across sizes. It is one of the most useful numbers on a shelf label.
Is the cheaper unit price always the best buy?
Only if you use it all. A bargain that expires half-used costs more than a small pack you finish.
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