grocery comparison shopping using unit pricing

October 13th, 2008

Grocery Comparison Shopping Using Unit Pricing

My goal in grocery shopping is to get to the point that the only things I am buying every week based on need are fresh items (fruits and dairy generally) and any item that can be stored (all cleaners, toiletries, pantry items, and all freezer items including meats) only when it is on sale.  This means I have to know when things are a good price, and know when I should stock up.  This is a different strategy than planning meals based on what is on sale – I buy a variety of items each week on sale and they are not necessarily for use that week.

A while back I wrote about how I compare costs of foods across different grocery stores based on keeping track of the unit pricing of items.   This is one of the specific strategies (coupled with coupons) I use to buy items at as low cost as possible.  It involves keeping track of what I pay for items, the size of the container of the items, and the final price of items after coupons.  I was asked to expand on how I do this, so I thought I would explain in more detail with examples.

Keeping track of what is paid for a certain container works if that container is all you ever buy.  However, with the onslaught of shrinking containers and different brands using different sizes, knowing the cost per container is not enough.  I could buy three different boxes of Raisin Bran at three different stores for the same price, and each box is a different size.  Which is where unit pricing comes in.

The setup is simple, but does take a bit of work.  I started by putting my grocery receipts into a spreadsheet each week.  Then I added in the sizes of the containers I bought.  I used the unit that made sense for the items – I used ounces for things like cheese and pasta and number of individual items for things like diapers and tampons.  Then I calculated what I paid per unit for each item.   I then, over time, determined what a “normal” price was for the item (basing my prices on Aldi generally) and what a really good price was for the item (based on sales data of what the lowest prices I paid was).


  • Item – Unit – Normal Unit Price (UP) – Good Buy UP – Buy Now UP
  • Pampers Diapers – 1 diaper – $0.36 – $0.28 – $0.24
  • Off-Brand Diapers – 1 diaper – $0.25 – $0.20 – $0.17
  • Shredded Mozz. cheese – 1 oz – $0.24 – $0.21 – $0.19
  • Boneless chicken breast – 1 lb – $1.99 – $1.89 – $1.79
  • Fruit and Grain bars – 1 bar – $0.22 – $0.20 – $0.15
  • Cereal – listed serving – $0.18 – $0.15 – $0.10

Some of these examples are lower than my original post (I have gotten better at couponing) and some are higher (because things just get more expensive by the day) but this is the general idea.  These prices will vary wildly by region, I am sure.  I live in the Midwest and many things are generally less expensive than the coasts.   As for the two different types of diapers, my daughter generally does well in certain off-brand diapers, but then for a week or two every few months, she’ll leak out of everything but Pampers.  Ah, growth spurts.  I keep them on hand for those times.  Oh, and my spouse likes them better.

I then go through circulars every week, and look at what is on sale.  I compare the coupons I have to the circulars, and I make two lists for each store.  One is  a list of buy now items, and the other is a list of items to check out at the store and make a decision there.  Sometimes the circular doesn’t have enough information in it for me to decide if it is a good deal or not.  I have a separate list of fresh items that we make throughout the week, and I add those items to the store list that has the best price that week.

And then I shop, and there you have it.  It takes more work than just shopping at one store, and it takes having a place to store items.  For example, a few weeks ago I got fruit and grain bars for $1/box at Kroger, which is $0.125 per bar.  I bought 15 boxes all told, and they are in my pantry closet.  15 boxes take up some room, but they don’t expire for many many months and we generally use 1 box per week.  And now I can wait until they are $1/box again.  :)

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11 Responses to “Grocery Comparison Shopping Using Unit Pricing”

  1. Unit pricing is definitely the way to go. For fresh foods, the quality is a consideration as well.

  2. Indeed, fresh foods I do consider the source – there are stores I will buy certain items at and stores I will not. I go for the least expensive of the stores I approve of on a weekly basis. :)

  3. The nice thing about my grocery store is that one every price label there is a price/ounce of food. That way I can write down the pricer per ounce of whatever I’m buying and also compare it to similar items next to it. It’s a great trick, and really helps me figure out what the best deal is!

  4. Great post. Now I’ve got to go home and rethink my entire shopping strategy! Thanks for the help.

  5. THANK YOU! Very impressive.

  6. I have a similar strategy and it works great. I upload my updated spreadsheet to Google Docs and can access it through my phone while I’m at the grocery store. Having access to my “price book” while I’m at the store is a huge help.

  7. Yeah, Dh always looks at the Unit price at the grocery store and notes whether its cheaper or not. I admit I don’t notice them very much. Saving is in the details…

    (Also wanted to note that I used one of your ING referrals from your link and wanted to say Thanks!)

  8. pay close attention to the unit prices. I am finding them to be inaccurate. ie: the unit price per ounce does not match the ounces in the package. When comparing products one unit price may be figured per ounce while the same product from a different manufacurer is figure by the pound, quart etc. I have been tricked into buying the more expensive product.The pre cut bags of lettuce were on sale. I checked the unit price for the 22oz. bag containing the 3 roman heart and the 12oz. bags of pre cut lettuce. with the sale price the unit price for the pre cut lettuce was cheaper. When I looked closer I noticed the roman hearts unit price was based on a 12oz. package not 22oz. The 3 roman hearts never come in a 12 oz pkg. Since the roman hearts were next to the pre cut lettuce, do you think this was an honest mistake or another way to trick people into buying the more expensive item?


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