Unit Price Calculator & Guide
Instantly compare the cost per kg, litre, or item to find the absolute best value for your money and stop overpaying at the supermarket.
Find the Best Value
Enter the price, quantity, and unit of measurement for two different products below to instantly see which one offers the better value for money.
Unit Price Comparator
Compare two items side-by-side.
How to Calculate
The simple math behind the best deal
Identify Total Price
Note the final shelf price of the product, ignoring any misleading “was/now” marketing unless the discounted price is what you will actually pay.
Identify Total Quantity
Find the net weight, volume, or item count. Ensure you are looking at the net amount, not the gross weight (which includes packaging).
Divide Price by Quantity
The formula is simple: Unit Price = Total Price ÷ Total Quantity. This gives you the cost per single gram, ml, or item.
Compare Like-for-Like
Ensure both items use the same unit (e.g., both in kg). The item with the lowest resulting number is the most economical choice.
Common Unit Conversions
Use these conversions to ensure you are comparing items using the same unit of measurement.
| Measurement Type | Conversion | Equivalent |
|---|---|---|
| Weight | 1 Kilogram (kg) = 1,000 Grams (g) | |
| Weight | 1 Pound (lb) ≈ 453.6 Grams (g) | |
| Volume | 1 Litre (L) = 1,000 Millilitres (ml) | |
| Volume | 1 Gallon (UK) ≈ 4.546 Litres (L) | |
| Count | 1 Dozen = 12 Items | |
| Count | 1 Gross = 144 Items |
Unit Pricing FAQ
Answers to the most frequently asked questions about calculating and comparing product values.
A unit price is the cost of a single unit of measure of a product, such as per kilogram, per litre, per 100 grams, or per individual item. It allows you to compare the true value of different sized packages of the same product.
To calculate the unit price, divide the total price of the item by its total quantity or weight. For example, if a 500g box of cereal costs £2.50, the unit price is £2.50 ÷ 500 = £0.005 per gram (or £5.00 per kg).
Not always. While larger packages often have a lower unit price, this is not guaranteed. Retailers sometimes use ‘shrinkflation’ or place promotional discounts on smaller items. Always check the unit price to be sure.
To make an accurate comparison, the units must be the same (e.g., both in kg or both in litres). If they differ, you must convert one to match the other (e.g., dividing grams by 1,000 to get kilograms) before comparing the unit prices.
In the UK, large supermarkets are generally required to show unit pricing on shelf labels. However, smaller independent stores, online marketplaces, or promotional “multi-buy” deals may not always display this clearly, making a manual calculation necessary.