Unit Price Calculator
Compare price per unit across pack sizes to find the best deal.
About the Unit Price Calculator
List each option on its own line with a name, its price and its quantity, using the same unit for every quantity (grams, millilitres or items). The calculator works out the price per unit, names the best value and says how much cheaper it is than the dearest option.
Bigger packs are usually, but not always, cheaper per unit. Only buy the bigger pack if you'll use it before it goes off.
The formula
Unit price = price ÷ quantity
Worked example
500 g for 3.49, 1 kg for 5.99, 2 kg for 10.49
- Per 100 g: 0.70, 0.60 and 0.52
- The 2 kg pack is the best value
- 24.9% cheaper per gram than the 500 g pack
Questions people ask
Why per 100 g?
Many shops label unit prices per 100 g or 100 mL; the calculator does the same when quantities are large.
Can I compare different units?
Convert them to the same unit first (1 kg = 1,000 g).
How do I compare multi-buy offers?
Enter the offer as one option: “3 for 5” on 400 g tins is price 5, quantity 1,200.