Price per unit calculator
Divide the price by the amount to compare like with like. A 500 g pack at £1.50 is £3.00 per kg, so it’s dearer than a 1 kg pack at £2.50 (£2.50 per kg).
Option B is cheapest
- Option A
- £3.00 per kg
- Option B
- £2.50 per kg
- Option C
- –
- Saving against the dearest
- 16.7%
Option B works out 16.7% cheaper per kg than Option A.
Value per unit isn’t everything: a bigger pack only saves money if you use it before it goes off.
Price per unit compared
Common pack sizes compared
Price per kg or litre at example prices.
| Pack | Price | Per kg or litre |
|---|---|---|
| 250 g | £1.00 | £4.00 |
| 500 g | £1.75 | £3.50 |
| 1 kg | £3.20 | £3.20 |
| 4 × 330 ml cans | £4.50 | £3.41 |
| 2 litre bottle | £2.20 | £1.10 |
Example prices only, to show how unit price changes with pack size.
How we calculate this
We divide the price by the total amount in the pack. Weights and volumes are shown per kilogram or litre, the same units shops must use on shelf labels under the Price Marking Order. Items are shown per item.
Questions people ask
Is the bigger pack always cheaper?
No. Multibuys and big packs are often cheaper per unit, but not always, especially when a smaller pack is on offer. Checking the unit price is the only way to know.
Where do I find the unit price in a shop?
On the shelf label, usually in smaller print, shown per kg, per litre or per item. Most shops must show it under the Price Marking Order, though some small shops don’t have to.
How do I compare kg with grams?
Turn both into grams first: 1 kg is 1,000 g, 1.5 kg is 1,500 g. Litres work the same way: 1 litre is 1,000 ml.
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