Unit Price Comparison Calculator
Type the price and size of each product, in any unit. You get the price per kilo, litre, item or metre, and which is the cheapest.
Fill in at least two products. Use units of the same kind, such as weights with weights.
Worked examples
Two packs of flour
500 g for £2.40 against 1 kg for £4.00
£4.80 a kilo against £4.00 a kilo
The smaller pack costs 20% more for the same weight.
About Unit Price Comparison Calculator
A unit price comparison calculator tells you which product is cheaper once the size is taken into account. Shop labels show a price for each unit, but different shops use different units, and the label is often small. Type the price, the size and the unit for up to four products and the tool works out the price per kilo, per litre, per item or per metre.
Multipacks are multiplied out, so six cans of 330 ml are compared as 1,980 ml. Weights, volumes, counts and lengths are each compared among themselves, and you can mix grams, kilograms, ounces and pounds in the same comparison. The cheapest is highlighted and the others show how much more they cost. A low unit price only saves money if you use the whole thing.
How to use Unit Price Comparison Calculator
- Enter the price, size and unit of each product.
- Enter the number in the pack if it is a multipack.
- Use at least two products of the same kind of unit.
- Read the cheapest and the percentage extra for the others.
Common uses
- Comparing sizes of the same item
- Choosing between brands
- Checking whether a multipack saves money
- Comparing shops
Frequently asked questions
How do I compare prices of different sizes?
Divide the price by the amount to get the price of one unit, such as per 100 g or per litre. Then compare. A £2.40 pack of 500 g is £4.80 a kilo, and a £4 pack of 1 kg is £4 a kilo, so the bigger one is cheaper.
How do multipacks work?
The tool multiplies the size by the number in the pack. Six 330 ml cans for £3 come to 1.98 litres at £1.52 a litre.
Can I compare grams with ounces?
Yes, as both are weights. The tool converts ounces and pounds to grams, so 16 oz is 453.6 g. You cannot compare a weight with a volume.
Is the biggest pack always cheapest?
Not always. Some shops charge more per unit for larger packs, so check. A big pack is also no saving if some of it is wasted.
What is shown for items?
For things sold by the piece, such as sheets or tablets, the price for each item. Use the items unit and enter the count.