Why is a baker’s dozen 13?
Probably to stay on the right side of medieval bread laws, or to give resellers a profit. Nobody can prove which, but bakers have long thrown in a 13th loaf.
Quick Answer
A baker’s dozen means 13, and there are two leading explanations. The popular one goes back to 1266, when England’s Assize of Bread and Ale tied the price of bread to its weight and punished bakers who sold short. Because loaves vary slightly as they bake, an extra loaf with every dozen was cheap insurance against coming up light. The Oxford English Dictionary offers another: bakers selling to retailers added a 13th loaf, and that extra loaf was the retailer’s profit. The phrase itself doesn’t appear in print until 1596, more than 300 years after the Assize, so no record directly ties it to the law. Either way, the idea is the same: one extra, to be safe or to be fair.
By the Numbers
Key Facts
- How many
- 13
- Popular explanation
- Medieval bread laws punished bakers who sold short weight
- Dictionary explanation
- An extra loaf as the retailer’s profit
- First in print
- 1596, in the writing of Thomas Nashe
Two explanations
| Bread-law theory | Retailer theory | |
|---|---|---|
| Who got the 13th loaf | The customer | The retailer reselling the bread |
| Why | Insurance against selling short weight | The retailer’s profit |
| Evidence | Fits the 1266 law, but no direct record | The Oxford English Dictionary’s explanation |
Bread sold by weight
The Assize of Bread and Ale, dating from 1266 under England’s Henry III, regulated the price, weight and quality of bread and ale. Bakers who sold loaves that came up short could be penalized.
Why one more loaf?
Bread doesn’t bake to exactly the same weight every time. Adding a 13th loaf to a dozen made sure the total never fell short of what the law required.
What the dictionary says
The Oxford English Dictionary traces the phrase to 1596 and explains it differently: bakers selling a dozen loaves to a retailer added a 13th, which represented the retailer’s profit.
Myth vs. Fact
MythThe 13th item was always a free gift for the customer.
FactOne leading explanation says the extra loaf was the reseller’s profit, not the customer’s bonus.
MythThe phrase dates back to the 1266 law.
FactIt first appears in print in 1596, more than 300 years later.
The Bottom Line
A baker’s dozen is 13 because bakers long added an extra loaf, either as insurance against strict bread-weight laws or as profit for the people reselling it. The first explanation is more famous; neither can be proven.