The Rationale For Odd Sizes

Have you ever wondered why some items come in odd weights and sizes? In this photo from the Marketplace website, notice the Ziploc quart-size freezer bags are packaged 19 to a box. Why the odd number?

An odd-size example from the Marketplace website.

I ran across this in an October 20, 2019 article entitled “The Marketing Tactics Behind Those Odd Weights and Sizes You See at the Supermarket” by Marielle Segarra (

According to Ms. Segarra, there are several reasons why manufacturers would use odd sizes.

When designing a package, the box size, product weight, and dimensions of the standard display shelf could result in an odd size, say 11.5 ounces instead of 12. But there are also marketing reasons.

Mark Bergen, a marketing professor at the University of Minnesota’s Carlson School of Management, thinks it’s probably what he calls the ‘difficult comparison effect.’ If a company’s product is not the cheapest option, they may try to make it more difficult to compare prices. Since only about a third of states require stores to post price-comparison labels, you frequently have to do the math, which can be too hard for many of us. So they hope you’ll use other decision-making criteria.

Also, downsizing a product can be preferable to raising the price. Instead of a price increase, subtract a bit from the contents, change the packaging, and hope no one will notice.

Of course, eventually customers do notice. But then it will be time to try another marketing strategy.

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