Writing numbers can be an essential component of daily paperwork and reports. Whether it’s quantifying accomplishments or enumerating specific dates, statistics and monetary figures, the task of writing numbers in formal documents can get pretty confusing. Consider the following guidelines and examples the next time you’re preparing to write with numbers:
- Single digit? It is common practice to write out the word for any number less than 10. Example: “They are requesting three printed copies of the report,” (preferred) vs. “They are requesting 3 printed copies of the report,” (not preferred).
- Avoid the percent symbol. Example: “One single project consumed 57 percent of my work hours this week,” (preferred) vs. “One single project consumed 57% of my work hours this week,” (not preferred).
- Hyphenate compound numbers when they appear in word form. For example, “thirty-seven or eighty-two, etc.”
- When communicating numbers with five or more digits, as is normal with budgets and grant writing, etc., remember to use punctuation appropriately. Example: “This year, 12,700 dollars were allocated towards new projects,” (preferred) vs. “This year, 12700 dollars were allocated towards new projects,” (not preferred).
- Write out ordinal numbers (numbers in a series). Example: “It was our fourteenth and final training,” (preferred) vs. “It was our 14th and final training,” (not preferred).
- Rounded numbers should be written out and exact numbers should appear as numerals. Example: “fifty thousand” or “one million” etc. Also correct, “53,453” or “1,486,320” etc., (all preferred).
- Write out numbers that start a sentence, or rearrange the sentence so the number appears in a different order. Example: “Seventeen paid days off per year is generally standard,” OR, “Generally, the standard is 17 paid days off per year,” (both preferred) vs. “17 paid days off per year is generally standard,” (not preferred).
- Dates and years generally appear as numerals, except when referring to decades and centuries. Ex., “In the nineties…” or, “At the turn of the twenty-first century…” (both preferred). Also, it’s easier to comprehend “January 27” (preferred) than it is to comprehend “January twenty-seventh” (not preferred).
- Things can get confusing when two numbers appear next to each other. In this case, it is best to write one of them out. Example: “I sent fifteen 450 page documents to the printer,” (preferred) vs. “I sent 15 450 page documents to the printer,” (not preferred).
- Consistency. Sometimes the rule for writing the word for numbers one through nine gets broken when there are multiple numbers in the same sentence that refer to the same thing. For example, “The project required just 3 hours of work the first week, but 17 hours the following week,”(preferred). However, when the numbers do not refer to the same thing, the single digit rule stands. For example, “There were 25 people in attendance at the two-hour training session,” (preferred).
Many of these best practices are not hard and fast rules, which can make the task of writing with numbers a big challenge. If you find yourself unsure of what to do, try referencing a style guide (popular ones include Chicago Manual of Style, MLA Style, and APA Style). If that’s no help, just remember to write with your readers in mind. Stick with a style that presents information clearly, is consistent with what’s already written and doesn’t distract from the written content.