About the Unit Price Calculator
Unit Price Calculator answers the question every shopper asks in the aisle: which one is the better buy? Enter the price, the size of one pack, the unit and the number of packs at that price for two to six products, and the tool works out the price of one unit for each, so a 500 gram pack and a 1 kilogram pack, or a three-for-two offer, can be compared fairly. Sizes can be in grams, kilograms, ounces, pounds, millilitres, litres, fluid ounces, items or metres, and the results can be shown per 100 g, per kilogram, per ounce, per pound, per litre and more. The cheapest product is highlighted, and each other one shows how much more it costs and what you would save. It all runs in your browser.
Updated September 2026
How to use the Unit Price Calculator
- 1For each product, enter the price, the size of one pack and choose its unit.
- 2If a price covers several packs, such as 3 for the price shown, enter the number of packs.
- 3Optional: give each product a name, add more products or remove ones you do not need.
- 4Choose how to show the price, for example per kg or per 100 g.
- 5Read the ranking, the best value and how much cheaper it is per unit.
Why unit prices matter
Shops price the same product in different pack sizes, and marketing tricks make it hard to see the true price. A larger pack is usually cheaper per unit, but not always, and a pack that looks smaller can hide a lower quantity. Some shops print the unit price on the shelf label, but the units can differ from one product to the next, one shown per 100 grams and the next per kilogram.
Working out the price per unit takes a calculator and a little patience. This tool does the sums for every product in one place, in the unit you choose, so the comparison is honest.
How to use it in the shop
- Take the price and the pack size from each label, including the unit.
- Use the packs field for offers such as buy three for a set price.
- Choose the display unit that the shop uses so you can check its shelf label.
- Give each product a short name so the ranking is easy to read.
- Look at the percentage extra to see how big the difference really is.
Beyond the price
A saving is only a saving if you use what you buy. Bulk packs of fresh food, cleaning products that lose strength and items that need storage space can turn a bargain into waste. Also compare quality and ingredients, since a cheaper product with more filler may give less for the money. For household budgets, small savings on items you buy every week add up to a real amount over a year.
If two products are close in price per unit, choose the one that fits how you use it. If one is far cheaper, check that the size and quality are as good as they look.
Related tools
Discount Calculator shows the price after a percentage off, Percentage Calculator works out how much more one price is than another, Unit Converter switches between grams, ounces and litres, Tip Calculator splits shared bills and Cooking Measurement Converter helps when a recipe uses different units from your shopping.
Features
- Compare two to six products
- Different sizes and units in the same comparison
- Multi-pack deals with a packs field
- Price per 100 g, kg, oz, lb, 100 ml, litre, fl oz, item or metre
- Best value highlighted with the percentage extra for the rest
- Saving shown on one display unit
- Currency symbol picker
- Runs in your browser
Frequently asked questions
What is the unit price?
It is the price of one standard unit of a product, such as one kilogram, one litre or one item. Dividing the price by the quantity lets you compare packs of different sizes. A 500 gram pack at 3.20 costs 6.40 per kilogram.
How do I compare a small and a large pack?
Enter each product's price and size, and choose the unit for each. The tool turns everything into a common base, such as grams, and shows the price per kilogram or per 100 grams. If the large pack is 1 kilogram at 5.50, it costs 5.50 per kilogram, which is cheaper than the small pack.
How do I handle a three-for-two or multi-buy offer?
Enter the offer price as the price and the number of packs you get for it in the packs box. If 3 packs of 200 grams cost 5.00 together, enter 5.00 as the price, 200 as the size and 3 as the packs, and the tool works out the price per unit for the whole deal.
Can I compare products in different units, such as grams and ounces?
Yes, as long as they measure the same thing. Weight units can be mixed, volume units can be mixed and items or metres compare with their own kind. The tool warns you if you mix weight and volume, because that comparison would not be meaningful.
Is the cheapest per unit always the best buy?
Not always. A bigger pack may cost less per unit but go off or be wasted before you use it, and quality and brand also differ. The unit price tells you the value, and you decide whether you will really use the quantity.
Why do the results show three decimals for small prices?
When a unit price is under one currency unit, such as 0.064 per gram, two decimals would hide the difference between products. The tool shows three decimals in that case so the comparison stays clear. Larger prices are shown with two decimals.
Does it work for non-food shopping?
Yes. Use it for washing powder, paint, bin bags, kitchen roll, pet food, batteries or anything sold in different pack sizes. Choose items or sheets for things sold by count and metres for things sold by length.