Unit price calculator
Enter the price, size and unit of each product. The calculator converts them to the unit of item A, shows the price per unit for each and tells you which one costs least.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter the price, quantity and unit of item A and item B.
- Switch on the third and fourth item to compare up to four products.
- The best value is the lowest price per unit; the saving compares it with the most expensive item.
Worked example
Item A is 3.00 for 500 g; item B is 5.00 for 1 kg. Per gram, A costs 3.00 ÷ 500 = 0.006 and B costs 5.00 ÷ 1,000 = 0.005. Item B is the best value, 16.67% cheaper than A, even though the pack costs more.
Tips
- Compare like with like: a “family size” is not always cheaper per unit.
- Unit price ignores quality, waste and whether you will use it all before it expires.
Frequently asked questions
How do I calculate the unit price?
Divide the price by the quantity: 3.00 for 500 g is 0.006 per gram. To compare products sold in different sizes or units, convert them to the same unit first; the calculator does that for you.
Which unit are the results shown in?
Per one unit of item A. If item A is in grams, every result is a price per gram, even for items entered in kilograms. Per-gram prices are small, so choose ounces or pieces for item A if you prefer larger numbers.
Can I compare weight with volume?
No. A kilogram and a litre are not the same thing, and the density of the product is needed to convert one into the other. The calculator reports a unit mismatch instead.
Which conversion factors are used?
1 kg = 1,000 g, 1 lb = 453.59237 g, 1 oz = 28.349523125 g, 1 l = 1,000 ml and 1 US fluid ounce = 29.5735295625 ml. UK fluid ounces are about 4% smaller, so UK shoppers should use millilitres.