The number 12 has significance throughout history. Some measurements are a legacy from a previous time for example the bakers dozen comes from 13th Century England. The word dozen itself has a Latin aka western origin. The logical answer to the question is 12 was used because it is one of the first Superior highly composite and Colossally abundant numbers, it is dividable by 2/3/4/6 so families of different sizes would benefit from a dozen. However the historical answer appropriate to this subreddit is the imperial system was common in England and Western Europe from 700-1960. 12 pence made a shilling so it make sense for it to be a penny an egg and a shilling for a dozen. In the 16th century eggs and bread were sold by the dozen and that was brought over to America and other places.

TL;DR The unit measure matched the currency measure for the time period and it remained thru history.

Source:--Prices, Food and Wages in Scotland 1550-1780, A.J.S. Gibson and T.C. Smout [Cambridge University Press:Cambridge] 1995 (p. 200)

May I piggyback a related question?

I have read that the "baker's dozen" -- 13, instead of 12 -- has its murky origins somewhere in Britain's past with bakers who, being faced with extremely stiff penalties for defrauding their customers, wanted to be beyond reproach if they were accused of selling products that didn't meet the minimum weight standard specified by the government at the time. Should they ever be accused of selling underweight items (i.e., defrauding their customers who expected items to contain a certain mass of grain flour), they could simply say "I'm not cheating my customers! See? I even give them extra!"

Is this accurate? I've read stories like this form multiple sources, but having no academic knowledge of history, I've no real way of knowing if this tale is scholarly or not.

Thanks!

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