Tip: See my list of the Most Common Mistakes in English. It will teach you how to avoid mis­takes with com­mas, pre­pos­i­tions, ir­reg­u­lar verbs, and much more.

It may come as a great surprise to the fans of The Lord of the Rings, but the correct traditional spelling of the plural of “dwarf” is “dwarfs”, not “dwarves”. When an English noun ends with a single “f” in the singular, the “f” usually changes to “v” in the plural, as in:

calf – calves; half – halves; wife – wives

There are, however, a few exceptions to the rule, e.g.

roof – roofs; chief – chiefs; oaf – oafs

and “dwarfs” used to be one of the exceptions. Nonetheless, J. R. R. Tolkien decided to use the spelling “dwarves” throughout his books instead. Or did he?

Tolkien himself admitted that “dwarves” was a misspelling. In a letter to Stanley Unwin, the publisher of The Hobbit, he wrote (emphasis mine):

No reviewer (that I have seen), although all have carefully used the correct dwarfs themselves, has commented on the fact (which I only became conscious of through reviews) that I use throughout the ‘incorrect’ plural dwarves. I am afraid it is just a piece of private bad grammar, rather shocking in a philologist; but I shall have to go on with it.

Modern usage of “dwarfs” and “dwarves”

The spelling may have started off as an error, but it has been living a life of its own and is now considered the standard spelling of the plural when referring to the fictional race created by Tolkien. Due to the books’ popularity, other fantasy authors commonly adopt the spelling as well. Take a look at the following graph showing the relative frequency of the nouns “dwarfs” and “dwarves” in English literature (created using Google Ngram Viewer):

When referring to the meanings of the word “dwarf” not related to fantasy, the plural “dwarfs” should be used, especially when referring to people in medical literature:

correct People with dwarfism are called dwarfs. unnatural People with dwarfism are called dwarves.

and to scientific objects: