Sunday, August 5, 2012

Calculating Unit Prices (Size 1 Diapers used as an example)

One of the easiest ways to save money long term on groceries is to calculate the unit prices when you shop. This is particularly helpful in my home stock room (which you can read about here).

The unit price is the price per a specific measurement of the product, usually ounces. It makes it easier to compare the prices of different sized items easily. Some stores list the unit price in a red or orange box next to the products price.

If the store doesn't list the unit price, you can calculate the unit price by dividing the cost of the product by the number of ounces (or other measurement) in the product.

I'll give you an example:


The following is a list of current Size 1 diaper prices for the location listed.

(WG)- Wegmans; (WM)- Walmart; (AZ)- Amazon; (TG)- Target
Except for Wegmans (where I do my grocery shopping), each location has free shipping.

1. (WM) Parents Choice Diapers - 200 ct. - $23.88
23.88 (cost of product) / 200 (number in product) = .12 per diaper (unit price)

2. (WG) Wegmans Diapers - 50 ct. - $5.99
5.99 / 50 = .12

3. (AZ) Luvs Diapers - 264 ct. - $35.99
35.99 / 264 = .14

4. (TG) Pampers - 276 ct. - $44.99
44.99 / 276 = .16

5. (TG) Huggies - 258 ct. - $44.99
44.99 / 258 = .17

6. (WM) Huggies - 192 ct.- $34.25
34.25 / 192 = .18

7. (WM) Pampers - 234 ct. - $47.19
47.19 / 234 = .20

8. (WM) Huggies- 40 ct. - $9.59
9.59 / 40 = .24

9. (AZ) Pampers - 192 ct. - $47.19
47.19 / 192 = .25

10. (WG) Pampers - 36 ct. - $9.59
9.59 / 36 = .27

11. (AZ) Huggies - 168 ct - $50.62
50.62 / 168 = .30

I would use this list to my advantage by buying a small pack of #1 (Parents Choice 200 count at, to see if I like the quality. If I do, then I would stock up on this diaper. Don't ever buy an untested product just because it's cheap. If you do, you'll end up with closets full of things that you bought but don't like.

If Pampers are the only brand that I'm willing to use, then I'm stocking up on #4 (Pampers 276 count at

I've been told (though I won't know for myself for a few more weeks), that babies use about 10 diapers per day. 10 diapers times 365 days in a year =  That's 3,650 diapers per year. (I just got dizzy when I realized that I have to change most of those!) If you were to plan poorly and pick up your Pampers Diapers at Wegmans each week with your groceries, you would spend $985.00 in a year on diapers (3,650 x .27). If you planned ahead and filled your stock room with appropriately sized Pampers Diapers from Target, you would spend $584.00 in a year (3,650 x .16). If you were lucky enough that Parents Choice Diapers or Wegmans Diapers worked just as well for you, you would spend $438.00 in diapers in a year.

In a year, you have the potential to save between $547.00 and $401.00 on just one product! What if you did this for just a few of your basic products. The things with long shelf lives that you'll never stop using. A few examples of these would be deodorant, hand soap, laundry detergent, shampoo, conditioner, baby wipes, toothpaste, etc. While I use quick unit price comparisons for grocery items, it's the stock room that comparing unit prices can make an enormous difference.

Start small and don't overwhelm yourself. Make a quick stock room list of things that you will always use. Then once a week, pick a product and do price comparisons online. I use Walmart, Target, Amazon, and Wegmans because I can find prices and product information right on the website and can get free shipping at each site (except for Wegmans, but I go there every week anyway). Costco or Sam's Club are also great resources if you have a membership. Eventually, you'll have your whole list whittled down to the best price and it will be easy to restock.
Photo courtesy of


  1. Another great post. It's been so long ago, I don't remember when it went dropped from the initial 170 diapers a week for Jon and Jen. It's mind boggling! :-)
    I do remember well that at justbshy of two years of age, they were out of diapers...which was a requirement for them to go to pre-school, so maybe they were incentivized a little!

    1. Jon says he'll have Michael out of diapers in 6 months... I'm trying to get him to agree to change all diapers past the 6 month mark if that plan falls through:)


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