Monday’s Grocery Theory post here, sneaking in just over the wire. So far Grocery Theory posts have introduced a ranking of Austin grocery stores, methods of storing when stocking up, the types of shopping we do, meat, and weekly planning.

Today’s topic: Unit Pricing.

You know what I’m talking about here. It’s that other number, usually on the shelf tag telling you how much your item will be.  Many people never take a look at that other number, some people will look at it to compare if they are buying an item they’ve got zero brand loyalty to follow, and others, well, others are always looking at them and doing the math.

It’s often surprising.  In a perfect store, these numbers should help you comparison shop, by letting you know this toothpaste is $X per ounce, and that one is $Y per ounce (don’t worry, algebra haters, we’re not going to keep using numbers where letters should be!).

Or say, eggs.  Eggs should be easy.  You’d like to know how much each egg is in the dozen you’re buying, compared to that dozen over there, or even compared to the 18-count over there.  Heck, go crazy and compare it to that big 2 1/2 dozen thing people only buy at Easter, why not?  It’s normal to expect the unit price to be per egg, and you’d have a second expectation of the price per egg being cheaper for the larger sizes.

Expecting something and finding it aren’t the same.

When is the last time you paid $34.69 for a dozen eggs?  Yeah, me neither.  This photo, taken by David S. Read and posted to his blog, is a great example of completely unhelpful, non-coherent unit pricing.  You look at the first one, and you realize, someone multiplied the actual price of a dozen eggs by 12.  That pattern works for a bit, ( with a hiccup for that 6-count at the top right, where they’re inexplicably multiplying by 2. because 6 is half a dozen?) but then there’s an 18 count egg carton, and they multiply that by 8 to get the unit price.  NICE!  But also deeply wrong.  Then it ends with unit prices per dozen, which seems to be the what they can handle even if it’s not a useful unit tool, because they got all of those right.  A dozen eggs cost as much as a dozen.  That’s a safe bet.

I saw this photo, and read his post, and was relieved.  For years I’ve thought I was the only person looking at unit prices, and now I know I’m not alone.  I thought I must be, because I’ve spent hours of my life in the toilet paper aisle (yes, this is a first-world problem I am having in the toilet paper AISLE.   I have multiple stores with aisles of tush-wiping paper.  I would be happier if there was one tp and I could just buy it and get on with my bad self!  Or if we all agreed to use leaves), trying to figure out what to buy.  At some point I’ll make a composite photo like the egg one, but toilet paper unit prices come in: sheets, sq. ft., sq. in., 1000 sheets, cm², and m².  Have you ever stood there trying to figure out how many square feet per roll, so you could make an even comparison?  I have, and it’s not simple.  You’ve got to look at the size of the sheet, get the area, multiply that by the number of sheets, and multiply by that, and then convert sq. inches to to sq. ft. so you can compare it to cm² …yeah.  That’s where even I stop and buy the one that seems cheapest per reasonably sized roll. I hate myself when I do that.

But it’s not just eggs and toilet paper.  I’m surprised all the time about the correct math that shows it’s cheaper to buy the smaller size of something rather than the larger (often, laundry detergent, soup, cereal), and by the wrong math demonstrated on the tags.   Listen, if something that’s 8 ounces is 99¢, then it’s safe to say it’s not $1.89 per ounce.

I feel like Common Core is trying to address this problem, with all of the estimates, and writing about how you got your answer.  But honestly, if you as a shopper don’t see this, your shopping isn’t doing right by your grocery budget. Knowing how unit prices work is one of the great ways to save.  The only thing that stops me from buying the cheapest thing per unit is brand loyalty, and I have very few of those (Hell-O Velveeta for queso!).

Unit prices, when correct, can help you. I use them all the time, especially when buying cheese, canned goods, rice, and beans.  You can too.  You don’t need a calculator, just look. In most cases, they’re right. If something seems hinky–pull up the calculator on your smart phone and see if your intuition is right.  That photo up there is an extravagant example of unit pricing being crazy.  If you saw a sticker that said unit price was over $20 for a box of macaroni and cheese, you’d stop, right?  In some terrible stores (HEB, you took unit prices OFF your eggs at Wm Cannon/S. 1st!) you don’t even have unit prices.  Texas doesn’t require unit pricing, and just last week I noticed that they’ve been removed in some areas, prompting my post.

How to Calculate Unit Price

Whenever you want to know the unit price? Look at what you’re buying. How much is it? Enter that into the calculator. Then, how big is it? This is the fiddly bit–if you are looking at a unit price, you want to match that, so if it’s per ounce (oz) that’s your number.  Then you divide by that number. That’s your Unit Price, which is Dollars per Amount of Stuff.

Comparing efficiently means matching units, so if you want to buy pasta, and you’re looking at different brands that are all 1lb each? Each one should have a label saying how much it costs, and also how much per lb. or per oz.  If some are not labeled that way,but instead are ‘per serving’ or per 8 oz., that’s when you need to start getting cranky.

Unit pricing is one of the best tools a grocery shopper has. If stores corrupt it, or don’t use it, it’s to the shoppers detriment. I encourage everyone to look at those unit prices. If the math doesn’t work, note it, and tell store management if possible. If there isn’t a unit price, and you want one, let them know that, too.  Use your grocery dollars in the very best way you can!