Illustration of grocery shelves, price tags, and a balance scale comparing packages.

Unit Price Calculator

Price per unit

Enter total price and quantity (items, kg, litres, or any unit you are comparing). Optionally compare a second pack size to see which is better value.

Unit price (first item)
Unit price (compare item)
Better value

Unit price = Total price ÷ Quantity. Use the same unit for both items when comparing (e.g. both in grams or both in items). Quantity can be a decimal (e.g. 0.5 kg as 500 g or 0.5 kg — stay consistent).

How unit pricing works

Compare like with like

Unit price is total price divided by quantity. Quantity can be items, kilograms, litres, sheets, or any consistent unit. Supermarkets print unit prices so a big bag can be compared with a small bag even when sticker prices differ.

Enter pack price and quantity for one offer. Optionally enter a second pack to see which has the lower price per unit.

Formula

Unit price = total price ÷ quantity. Lower unit price is better value if the product is equivalent (same quality, same waste, same extras).

Worked example

Pack A: £3.00 for 500 g → £6.00 per kg. Pack B: £5.00 for 1 kg → £5.00 per kg. Pack B wins on unit price even though its shelf ticket is higher.

Practical tips

  • Convert both packs to the same quantity unit before comparing.
  • Watch for concentrated products (dilute-to-taste cleaners) where “per litre as sold” is unfair.
  • Factor spoilage: a cheaper bulk unit price wastes money if you throw half away.

Common mistakes

  • Comparing per item with per kg casually labelled “unit.”
  • Ignoring multi-buy offers that change the effective total price.
  • Forgetting deposit or membership fees that change true cost.

FAQs

Does discount change unit price?
Yes — use the price you actually pay. Estimate sale prices with Discount first if needed.
Can quantity be fractional?
Yes. Use litres, kg, or any decimal quantity that matches the label.

Related: Discount, VAT / Sales Tax, Percentage.

Last updated: July 2026