UnitWise UK

Why I made this tool

Standing in front of a shelf with a large pack, a small pack, a loyalty price and a multibuy can feel like a maths test. I built UnitWise UK so the arithmetic is done consistently. It tells me the real unit cost; I still decide whether I can use the larger pack before it goes to waste.

What it helps with

Weight, volume and item-count comparisons, including ordinary prices, loyalty prices, multibuys and drained weight.

When it is most useful

1. Comparing large and small packs with different quantities.
2. Comparing labels shown per 100g and per kilogram.
3. Checking whether a loyalty or multibuy offer is really cheaper.
4. Using drained weight when that is the amount you can actually eat or use.

Before you start

1. Product name and price.
2. Weight, volume or item count.
3. Any loyalty or multibuy details.
4. Drained weight where relevant.

How to use it

1. Choose weight, volume or count; keep every product in the same comparison type.
2. Enter the first product’s price, quantity and unit.
3. Add loyalty, multibuy or drained-weight information where relevant.
4. Add the other products and calculate.
5. Compare the standardised price per kg, 100g, litre or item.

How to read the result

The lowest unit price is the cheapest on a like-for-like quantity basis. It does not automatically mean it is the best purchase for your household.

What it cannot do

1. It does not judge quality, taste, shelf life, storage space or likely waste.
2. Concentrated or substantially different products may not be comparable by unit price alone.
3. Offers and eligibility can change, so check the checkout price.

Data and privacy

Frequently asked questions