Compare packages by calculating the price per item, per kilogram or per any unit you choose.
Example
A pack of 3 items costing 12 has a unit price of 4. To compare two products, enter A as 750 g for 18 and B as 1 kg for 26, with both quantities in kilograms (0.75 and 1). A costs 24 per kilogram and B costs 26, so A is cheaper by 2 per kilogram, about 7.69% less than B.
Calculation method
The unit price is the total price divided by the quantity, weight or volume you enter, in whatever unit you typed: grams give a price per gram and kilograms a price per kilogram. Results show up to 12 significant digits, so 3.49 for 500 g appears as 0.00698 per gram instead of being rounded to 0.01. When the division does not end, the display is a rounded approximation: 7.99 for 1.2 kg shows 6.65833333333, while the exact value repeats the 3 forever. The quantity must be greater than zero.
Important notes
For a two-product comparison, enter product A and product B in the same currency and the same unit; product B is optional. The tool shows both unit prices, which product is cheaper and how much less it costs as a percentage of the higher unit price. Mixing units gives a meaningless answer: 750 entered in grams against 1 entered in kilograms compares 0.024 per gram with 26 per kilogram. Add shipping, tax or deposits to a price only if you will actually pay them.
Enter the price and quantity in one unit
The unit price is the total price divided by the quantity, in whatever unit you type the quantity in. A pack of 3 items costing 12 gives 4 per item. 3.49 for 0.5 kg gives 6.98 per kilogram, and the same pack entered as 500 g gives 0.00698 per gram. Results show up to 12 significant digits, so a small per-gram price is not rounded to 0.01; pick the unit that is easiest to read, not to gain precision. When the division does not end, the display is a rounded approximation: 7.99 for 1.2 kg shows 6.65833333333, while the exact value is 6.658333… with the 3 repeating forever. If you note it as 6.66 per kilogram, treat that figure as approximate. The quantity must be greater than zero; 0 is not accepted.
Compare two products and read the result
Fill in product A and, optionally, product B, using the same currency and the same unit for both. Suppose A is 750 g for 18 and B is 1 kg for 26. Entering the quantities in kilograms (0.75 and 1) gives 24 per kilogram for A and 26 for B, so A is cheaper by 2 per kilogram. The saving is that gap divided by the higher unit price: 2 ÷ 26, about 7.69%. Entering 750 and 1000 grams instead gives 0.024 and 0.026 per gram, a gap of 0.002, with the same conclusion and percentage. What breaks the comparison is mixing units: typing 750 for A in grams and 1 for B in kilograms compares 0.024 per gram with 26 per kilogram and makes A look far cheaper than it is. Leave product B empty when you only need one unit price.
Decide what goes into the price
The tool divides exactly the numbers you enter, so add shipping, tax or deposits to each product’s price if you will really pay them, and subtract a discount only if it applies at checkout. If only one option has a delivery charge, adding it can reverse the result. Multipacks work the same way: six cans for 5.49 cost 0.915 each, which you can compare with the single-can price. A lower unit price only saves money if you use the whole quantity; a large pack that spoils or expires before you finish it costs more per portion you actually use. Shelf labels in some countries already show a unit price, but similar products may be labelled per 100 g, per kilogram or per item, so convert before comparing.
Worked examples| Input | Result |
|---|
12 / 3 | 4 |
3.49 / 0.5 kg | 6.98 |
7.99 / 1.2 kg | 6.65833333333 |
5.49 / 6 | 0.915 |
3.49 / 500 g | 0.00698 |
Frequently asked questions
Is 6.65833333333 the exact unit price?
No. The display keeps up to 12 significant digits, and 7.99 divided by 1.2 never ends, so 6.65833333333 is a rounded approximation of 6.658333… If you write it down as 6.66 per kilogram, treat that as approximate. Results that end, such as 0.915 or 0.00698, are shown in full, and small per-gram prices are not rounded to 0.01.
How is the percentage saving calculated?
It is the gap between the two unit prices divided by the higher one. With A at 750 g for 18 and B at 1 kg for 26, the unit prices are 24 and 26 per kilogram, so A saves 2 ÷ 26, about 7.69%. Entering both quantities in grams gives 0.024 and 0.026 per gram and the same percentage, because only the ratio matters.
Is the lower unit price always the better buy?
Only if you will use it. Six cans for 5.49 cost 0.915 each, but a large pack that spoils or expires before you finish it costs more per portion you actually use. Add tax or delivery to each price when they differ between the two options, and check that shelf labels use the same unit before comparing them.