Spelling Numbers

Single-digit Numbers

Spell out numbers under eleven. Yes, I’m aware ten is not a single-digit number, but can you imagine a world where we excluded ten from this rule. Imagine I wrote eight, nine, 10 in a sentence. Now can you see how horrible the world would be in that case?

Best Practices of Single-digit Numbers

All jokes aside, best practices, as well as most (if not all) professional manuals of style dictate that when writing out numbers, spell the number out when it is a single digit, and write the actual number itself for values that are multiple digits.

Some style guides will include the number ten in this rule, and some style guides will not include 10 in this rule. Personally, I obviously favor including ten, because it is such a short number of letters in the word that it makes sense to include it. There are some style guides that suggest spelling out all numbers less than twenty. Personally, I doubt anybody reads those style guides anymore, so they don’t count. Some people might decide to spell out numbers less than 13, and I do not oppose that rule, but I personally do not subscribe to that rule. I would suggest allowing personal preference to act as a guide while closely adhering to the general principles of this rule.

I believe this rule is especially true for numbers in a list. When listing numbers, if the first one is spelled out, then the rest should be spelled out. If the first is written in numerals, then the rest should be written in numerals. This exception is the result of the rule on Parallelism, which supersedes this rule when there is a conflict.

Exceptions

Besides from lists that follow the rules of parallelism, other exceptions include section titles or headers, such as Chapter 1; outline numbering, such as the case when a list has numbering before each item; writing checks, which demand large numbers be spelled out in a tiny space in the middle of the check; in quoted speech or quoted text, such as “...she counted 1, 2, 3...”

Other exceptions may exist, but it’s best to use common sense, personal preference, and sound judgment before adding anymore exceptions to this rule.

Summary

In conclusion, it is best practices to spell out the numbers less than or equal to ten and write the numerals of numbers 11 and greater.

Following style guides when it comes to numbers should allow for a certain amount of personal preference to dictate how closely someone adheres to this rule.

And finally, if you are a good person, then you will spell out the number ten unless it is in a list where the first number isn’t spelled out.