Using numbers in one’s writing is often inevitable, especially when you write non-fiction. An article you are writing may require the numbers or figures from studies, surveys, or experiments to support your argument. However, using numbers can be confusing. After all, sometimes you will need to spell out the numbers, and other times you will require you to use numerals. Knowing when to spell numbers out as words and when to write them as numerals will depend on which style manual you are using and whether or not the publication you write for has a “house style.” This article will provide a few general rules to help in case you don’t have access to one of these manuals or when guidelines may otherwise be unclear. Keep in mind, this article will be focusing on nontechnical contexts.
General Guidelines For Use of Numbers
Various factors will help determine whether you need to spell out numbers or use numerals. Some of these factors include whether the number is large or small, whether it is a specific quantity or an approximate number, the context of the number, and what it is representing. However, both The Chicago Manual of Style and The Associated Press Stylebook both offer a few general rules that will be summarized here.
If you are using AP style, you will need only spell out single digit numbers (one through nine) and use figures for 10 and above. However, The Chicago Manual of Style recommends spelling out whole numbers one through one hundred.
AP: The building was 50 years old.
CMS: The building was fifty years old.
Treatment of Larger Numbers
Rounded numbers (hundreds, thousands, millions, etc.) are generally spelled out, but really large numbers (millions or more) can be expressed with a mixture of numerals and spelled out numbers.
Two hundred people attended the wedding.
New York City’s population is estimated at about 19.3 million.
Numbers at the Beginning of a Sentence
Occasionally, you may need to begin a sentence with a number. In this case, the number should be spelled out whether it is large or small, round or specific. If spelling out the number seems too long or awkward, it would be best to rewrite the sentence. Consider the examples below.
One hundred and forty-five of the applications were reviewed.
If you don’t want to write out the number, consider rewriting it like this.
In all, 145 applications were reviewed.
Whether you prefer one method over another, make sure you are consistent. If you have a list of numbers, you may have to conform to one method or another for the sake of consistency and readability.