What it does
The big pack is not always the cheap one, and shelf labels often use different units. Type the price and the size of each product and this page converts them to one common unit, so you can see at once which is the better deal. The cheapest row is marked in green, and the page says how much less it costs than the dearest.
It converts weight (g, kg, oz, lb), liquids (ml, L, US fl oz), counts and sheets, so a product in ounces can be compared with one in grams. For a bigger saving, check a promotion with the percentage calculator, and see where it fits in your budget.
How to use it
- Type a name, the price, the quantity and the unit for each product. Two products are ready for you; add up to six.
- If a price is for a multi-pack, put the size of one item in Quantity and the number of items in Packs. Six 330 ml cans is 330 ml with 6 packs.
- Read the table and the sentence above it.
What the columns mean
- Price: what you pay for the whole pack.
- Compared: the price per 100 g, per litre, per item or per 100 sheets, whichever fits the unit.
Weight, liquids and counts cannot be compared with each other, so the page asks you to keep to one kind.
Worked example
Pack A is 500 g for 4.00, which is 0.80 per 100 g. Pack B is 1 kg for 7.00, which is 0.70 per 100 g. Pack B is cheaper per gram even though it costs more at the till, and you save 12.5% by choosing it. Only buy the big one if you will use it before it spoils.
FAQs
Why are there no mixed comparisons like grams against litres? They measure different things. Density would be needed, and it differs for every product.
Are US and UK fluid ounces the same? No. This tool uses the US fluid ounce.
Should I always buy the cheapest per unit? Not if you will waste some of it.
Where the numbers come from
- Conversions: 1 oz = 28.349523125 g, 1 lb = 453.59237 g, 1 US fl oz = 29.5735295625 ml (international standard definitions).
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.