Sterlingsum
Unit price calculator
Enter the price and size of up to three products to see which is the best value per 100g, per 100ml or per item.
Runs in your browser. Last reviewed 5 October 2026. Spotted a mistake? Tell us.
Which is the best value
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Why compare the price per unit
The shelf price rarely tells you which product is the better buy, because packs come in different sizes. The price per 100g or per 100ml puts every product on the same footing. A bigger pack is not always cheaper per unit, and a smaller pack on offer sometimes beats the big one.
Enter the pack price and size for each product. For a multipack, put the size of one item and the number of items, for example 6 packs of 330ml. All sizes are converted to a common unit, so you can mix grams and kilograms or millilitres and litres. Weight, volume and items cannot be compared with each other.
For more ways to bring the bill down, see our guide to cutting your food shop.
What this calculator assumes
- Prices are the pack price you pay, including any offer.
- Weight is compared per 100g, volume per 100ml, and items per item.
- It does not allow for quality, waste, nutrition or how much you will actually use.
Questions people ask
How do I compare a multipack with a single item?
Enter the size of one item and the number of packs in the deal. For example, 6 cans of 330ml is a size of 330, unit ml, and 6 packs. The calculator works out the price per 100ml for the whole deal.
Why is the bigger pack not always cheaper?
Manufacturers and shops price packs differently, and offers on small packs can beat the large size. Comparing the price per 100g or 100ml shows the real difference.
Can I compare weight with volume?
No. Grams and millilitres measure different things, so the calculator only compares products in the same kind of unit: weight, volume or items.
Does this calculator send my details anywhere?
No. It runs in your browser and nothing you enter is sent to us. Our privacy page has the details.