Grocery unit prices: compare baskets across pack sizes

Specify the product and quantity

Write a shopping list with quantities and product definitions: milk by litre, rice by kilogram, eggs by count and other items in appropriate units. Keep product quality and form comparable. Fresh, dried, prepared and drained products can have different useful quantities; a package weight alone may not describe the food you actually intend to eat.

Calculate the unit cost

Illustration only: a 750 g package at 3 costs 4 per kg; a 1 kg package at 3.80 costs 3.80 per kg. This comparison assumes equivalent products and that you use the contents. If the larger package creates waste or requires a membership fee, record that separately. Promotions that require multiple purchases should not replace the ordinary price unless you will meet the conditions.

Scale the basket, not a random handful

Multiply comparable unit prices by your intended quantities, then total the basket. Mark missing items and keep dates and store context. A sum of five convenient products is not a complete monthly food budget. Add only quantities you actually need, and keep household cleaning goods, delivery and restaurant meals separate so differences between cities can be explained.

Sources and further reading

• Lifovra — methodology and limitations