Unit Price Calculator
Unit price is the price divided by the quantity, expressed per gram, per litre or per 100 g, and it is the only figure that compares two packs of different sizes fairly. The arithmetic is one division; the discipline is applying it before you trust a label.
Price per gram
0.006
- Price per 100 grams
- 0.6
- Grams you get per unit of currency
- 166.6667
- Price per kilogram
- 6
Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.
The formula this calculator uses
Unit price = price / quantity
- P
- Price of the pack, in your currency
- Q
- Quantity in the pack, in grams, millilitres or pieces
- U
- Unit price — the comparable rate you actually rank
- C
- Common reference unit, such as 100 g or 1 kg, used to normalise
How to check the result by hand
- 1
Read the net weight, not the size claim
Ignore words like large, family or jumbo and find the net weight printed in small type. That number, not the box, is the quantity you divide by, and it is also where shrinkflation hides.
- 2
Divide the price by the quantity
4.50 divided by 750 g is 0.006 per gram. Keep the units attached so you can see what the rate means, and do the same division for every pack you are weighing up.
- 3
Normalise to a shared unit
Scale each rate to the same reference, such as 100 g or 1 kg. Here 0.006 per gram becomes 0.6 per 100 g and 6.0 per kilogram, which are easy to hold side by side.
- 4
Compare the rates, not the totals
0.6 per 100 g against 0.56 per 100 g shows the 1 kg pack winning by 0.04, or about 6.6666667%. Totals of 4.50 and 5.60 would have suggested the opposite conclusion.
- 5
Adjust for waste, shelf life and quality
Scale the rate by any fraction you expect to waste, check that you can finish the pack before it spoils, and only then let quality and fit break any remaining tie between packs.
For worked examples, common mistakes and the limits of this formula, read the full How To Calculate Unit Price page.