Cartons of Eggs

For real, we have to ask ourselves why eggs are sold as 12. I could just assume it was accepted like that but really, why didn't they make it a perfect 10? Selling eggs by the dozen is a practice that has been around for a really long time. I had to do my research and I found out. The reason we have 12 eggs in a box is because of the historical commercial, legal and practical reasons for counting by a dozen. I don't think it's just one person that came up with it, I think it has developed with the systems that have been in place over time. I see it as it has been a progressive system.

For hundreds of years, merchants in North America and Europe have used dozens because 12 is an easily divisible number, making it simple to split and to price it because obviously they'll trade with it. A box of a dozen eggs is easily packable in a 2 by 6 and a 3 by 4 configuration. But if it was a set of 10, it would also work in a 2 by 5 box, but you can’t pack a half unit of 5 so that won't work. The main reason for eggs to be sold in dozens is the convenience of the packaging.

Imperial Units started being used in the UK and in Western Europe a long time ago. With the Shilling system, 1 shilling is 12 pence. This means that selling an egg for a penny or a dozen eggs for a shilling meant no change had to be given. Selling eggs in singles or by the dozen was made easier using this pricing system.

In the last 10 years in the UK, there was a real shift towards selling 10 egg cartons and selling eggs in larger quantities like 15 and 24. Most countries have metric systems. But they still seem to have a dozen eggs in a carton.

So from what I've learned, nobody did it, it's just basic math of the packaging ease.