Per is the easiest, fastest way to compare price while you shop.

Download Per on the App Store

Per helps you shop smarter by figuring out what gets you more for your money.

At its heart, Per is a price-per-unit calculator. Just give it the price and quantity for two options, tap the Compare button, and let Per figure out which one gives you the best deal.

Of course, you can do that kind of math with a basic calculator app. Per brings a few neat little tricks to the comparison-shopping party, though.


Bang for your buck.

Image of Per result indicating how much more you get for your money with the winning option.

Just because you’re getting more for your money, doesn’t mean that it’s a good buy.

Maybe you’re not sure you’ve got the space to store eighty rolls of toilet paper.

Or that you can get through sixteen heads of lettuce before they spoil.

Per tells you just how much more you’re getting for your money, so you can make those decisions confidently.

Convert between units.

Image showing Per's built-in unit conversion.

Making a decision between two options is even more annoying when they’re in different units. Millilitres versus fluid ounces. Grams versus pounds. And so on.

Maybe you have a conversion app to help. Maybe you rely on your search engine.

Or maybe you can let Per simplify your grocery run.

Just select the type of unit (weight or volume), and then choose the units for each product. Tap Compare, and Per will sort out all the details for you.

Forget the calculator.

Image showing Per's in-line calculator


Buy two, get one free?

Double rolls?

Per’s input toolbar lets you enter simple equations, so that you never have to switch to your calculator app. Just plug in the math, and the calculation is updated automatically.


In my area, retailers are required by law to indicate the price per unit. Why would I need Per?

These laws don’t always require the vendor to use a common unit for easy comparison, and they also may not apply to sale-price items. And when you’re looking at what amounts to fractions of a penny per unit, it’s hard to tell exactly how good a deal that price may be. Per’s features help in all of these cases.

Per’s unit conversion isn’t exactly accurate.

That’s not exactly a question, but it is a good point.

You have to strike a balance between accuracy and practicality. While 16 fluid ounces are equal to 473.176473 mL, you’d be hard pressed to find any packaging facility that can actually meet this kind of precision, so Per uses the more commonly-accepted 473 mL conversion instead, because this will give a more useful and realistic unit-price result.

Does Per’s conversion feature handle UK measurement units?

Yes! When the app first launches it’ll set Imperial measurements for the region you’re in. You can change this at any time by tapping the menu button and changing your selection.

Why can’t I enter complex equations, like 7 × 25 + 6 ÷ 3?

It’s a bit complicated to make this work in a way that people expect, due to operator precedence in mathematics. In the meanwhile, you can always enter a first equation (7 × 25), then go back and enter the next part of the equation (+ 6), and so on.

I have a question not covered here.

You should definitely get in touch via e-mail or Twitter and let me know how I can help.