Grammar-ease: When to write out numbers

Welcome to a new grammar post, lovely readers. This topic came from one of you, thank you!

When do you write out numbers?

Some consistent rules include:

  • Write out small, whole numbers that are less than 10: one, two, three, four, five, six, seven, eight, nine
  • Write out centuries and decades: twenty-first century, the Seventies
  • Write out a number if it starts a sentence: Six hundred men stormed the castle. (An exception is if the sentence starts with a year: 1965 was a great year.)
  • Estimated and rounded numbers over a million are a mix:
    2 million, 47 billion, 598 trillion (exact numbers are written out: 1,734,683,925; 1,985; 99,234, and so on)
  • Similar to the above point, percentages, when a whole number, spell out; with decimal or fraction, use the number: thirty-seven percent (or 37 percent); 2.75%, 3 3/4%, ten percent (or 10 percent).
  • When two numbers are next to each other, spell one of them out: I had a party for 4 ten-year-old children; ten 4-year-old children(spell out the number with the fewest letters)
  • Multiple numbers in a sentence — your choice to spell out or not, but be consistent with the method you choose: There were 11 horses, 6 chickens, and 2 ducks on the farm. OR There were eleven horses, six chickens, and two ducks on the farm. (Not, for instance: There were 11 horses, six chickens, and two ducks.)

Rules that vary:

  • Spelling out a number in a quote. If something is a direct quote, I prefer to spell out numbers as words; but it is okay to use numbers: Robert said, “I found 57 pieces of glass on the beach.” OR Robert said, “I found fifty-seven pieces of glass on the beach.”
  • Unless following a specific style guide, it’s generally a personal preference whether to write out single-word numbers (thirteen, thirty, forty, and so on) or use figures for two-word numbers (25, 31, 46, 99 and so on). Numbers containing three or more words fall into the category about about estimated/rounded numbers versus exact numbers.
  • Time of day is a personal preference: 4:30AM versus four-thirty in the morning; The alarm goes off at five sharp. versus The alarm goes off at 5 sharp.

Here’s a way to keep it simple:

The overall rule of thumb: consistency is key.

Of course this doesn’t cover every rule or possibility, just an overview and place to start. Publishers and many companies have style guides that spell out their preferences, and you’ll (probably) seldom find any two alike!

LisaJJackson_2014Lisa J. Jackson is an independent writer and editor who enjoys working with manufacturing, software, technology, and realty businesses of all sizes. She loves researching topics, interviewing experts, and helping companies tell their stories. You can connect with her on TwitterFacebook, and LinkedIn.

14 thoughts on “Grammar-ease: When to write out numbers

  1. Your last point is very important. Check the style guide. I’ve writing documents for a number of tech companies and more than once was surprised to find an in house style guide with very specific requirements that forced me into a few hours of editing.

  2. Thankis for this! It’s really useful. There are certain strict rules at my dayjob (as a translator), so once in a while I get unsure when it comes to my fiction writing. – It’s good to see I’m not completely off. 🙂

  3. I’ve often wondered about this. I generally spell numbers out because I wasn’t sure when to spell/when to use the number so I’ve been consistent. 🙂 Thanks for the tips.

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