A free unit price calculator that compares up to 4 sizes in any units and ranks them by the price for the same amount.
Compare up to 4 sizes in any units and see which is the best buy, and by how much.
Your numbers
Mix units freely: grams beside pounds, liters beside fluid ounces. Use Pack of for multipacks, like 6 cans of 330 ml.
Your result
Fill in the fields above to see your result.
Embed this tool on your site
Paste the code into any page: WordPress, Webflow, Squarespace, Ghost or plain HTML. It's free with the credit under it, which links back to navid.me.
This free unit price calculator compares up to 4 sizes of the same thing and shows which is the best buy, and how much more the others cost for the same amount.
It mixes units freely: grams beside pounds, liters beside fluid ounces, single cans beside 6-packs.
I built it because shelf labels use different units for different sizes, and "the big one is always cheaper" is wrong often enough to cost you. Here the math is done for you.
Here's how unit prices work, a worked example, and when the cheapest per unit isn't the best buy.
TL;DRKey takeaways
What is a unit price calculator?
A unit price calculator divides each price by its size, in one shared unit, so different sizes can be compared fairly.
It's the number on a shelf label's small print, the price per kg, per liter or per item. This calculator works it out when the labels don't, or when they use different units.
How to use the unit price calculator
You need each size's price and amount.
You can add up to 4 items, and name them so the result is easy to read.
A worked example
Here's the example the calculator loads when you press Try an example: 3 sizes of rice.
- Price
- $12.99
- Size
- 5 lb (2.27 kg)
- Per kg
- $5.73
- Price
- $5.99
- Size
- 1 kg
- Per kg
- $5.99
- Price
- $3.49
- Size
- 500 g
- Per kg
- $6.98
The family pack is the best buy. The big bag costs about 5% more for the same amount, and the small bag about 22% more.
When the cheapest isn't the best buy
The lowest unit price only saves money if the extra gets used.
It goes off before you finish it
Fresh food, opened sauces and anything that expires can cost more in waste than the bigger size saved.
You don't have the room or the cash
A bulk pack ties up money and shelf space. That's fine for rice, and less so for something you buy twice a year.
The deal is on the small size
Offers often land on smaller packs. With a discount, the discount calculator gives the real price to type in here.
Mistakes to avoid
These are the ways shoppers pay more per unit without noticing.
- Assuming the biggest pack is always the cheapest
- Comparing a price per item with a price per kg
- Forgetting the number in a multipack
- Ignoring how much of the big size goes to waste
When you shop in another country, the currency converter turns the best buy's price into your own money.
Who is the unit price calculator for?
It's for anyone doing the weekly shop or buying in bulk, and these tools help around it.
- Discount calculator – for the price after an offer
- Percentage calculator – for any other percent question
- Currency converter – for prices abroad
- Electricity cost calculator – for what an appliance costs to run
- Gas trip calculator – for whether the drive to a cheaper store pays
Type 2 sizes, and the best buy shows itself.
Plan your money with your AI
Take your numbers further in
Unit Price Calculator FAQs
Questions about the unit price calculator? Here's what to know.
A unit price calculator works out the price per kg, per liter or per item, so different sizes can be compared.
This free one compares up to 4 items in any units.
Divide the price by the amount, in the same unit for every item.
So $5.99 for 1 kg is $5.99 a kg.
Convert both to the same unit first: a pound is 453.6 g.
The calculator does it for you when you pick each item's unit.
No.
Multipacks and family sizes sometimes cost more per unit, and offers often land on the smaller packs.
Type the size of one item and the number in the pack.
6 cans of 330 ml is 1.98 liters.
Grams, kilograms, ounces and pounds; milliliters, liters, fluid ounces, cups, pints, quarts and gallons; and items, sheets or loads.
Either gives the same best buy.
Use the one your shop's labels use, so you can check them.
Only if you use it all before it goes off.
Waste can cost more than the bigger size saved.
Yes, it's free with no sign-up.
It runs in your browser.
I did.
I'm Navid Moazzez, and I made the unit price calculator as one of my free tools on navid.me.
More about me.
Navid Moazzez
AI business strategist & AI OS builder
Navid Moazzez helps creators and founders master AI and build their own AI Operating System (AI OS) to automate their business and life.
Navid.me is reader-supported. When you buy through links on this site, I may earn an affiliate commission. Learn more.
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