Which is cheaper per unit?
Type the price and size of two to four products. The answer appears as you type. Nothing you type leaves your browser.
Product 1
Product 2
Product 3
Product 4
Changing a unit keeps the number you typed and only changes its label. It does not convert it.
How it works
For each product the page divides the price by the total size. The total size is the size times the number of packs. The result is the price in the money you typed, per one unit. Six packs of 330 mL at 4.50 is 4.50 divided by 1980 mL.
Every unit is first turned into grams, millilitres or a count. The page uses exact fractions, with no floating point, so two close prices are never put in the wrong order by rounding. The ranking uses the exact value. Only the number shown is rounded, to 4 decimals, halves up.
The constants
- 1 lb = 453.59237 g
- 1 oz = 28.349523125 g
- 1 US fl oz = 29.5735295625 mL
- 1 UK fl oz = 28.4130625 mL
- 1 kg = 1000 g, 1 L = 1000 mL
What "X% more" means
Each other product's price per unit divided by the cheapest one, minus 1, as a percent, rounded to a whole percent. Under 1% it says "under 1% more". Equal prices per unit are all marked "Same price per unit".
Changing a unit
Changing a unit keeps the number you typed and only changes its label. It does not convert it.
What it refuses
Weight and volume cannot be compared, because a gram of one thing and a millilitre of another are not the same amount. Prices and sizes must be above zero and use a dot for decimals, so 1,50 is refused instead of being read as 150. Packs are whole numbers from 1 to 999.
What it does not cover
Quality, coupons, tax, waste and how long something keeps. Cheapest per unit is not always the best buy: it does not know what you will use or how long it keeps.