When to Spell Out Numbers

Knowing when to spell out numbers and when to use numerals can be confusing.

It generally depends on what you’re writing. For example, if you’re writing a scientific article, you’ll need to use numerals to express units of measurement. But if you’re writing a short story, a numeral looks weird and takes you out of the flow of the reading.

Here are a couple general rules of thumb.

Generally, spell out numbers under 101

When you're writing for general purposes (aka not science), you should spell out all numbers from zero to one hundred.

• ex: I worked there for ten years. I can't tell you how many times I saved her a**. Fifty times at least.

Of course, there are times when this doesn't make sense. The exceptions are:

• percentages

  • ex: I think I saved her a**, like, 50% of the time.

• years and dates

  • ex: I’ve worked there for ten years—so since 2011.

• page and chapter numbers

  • ex: The quote is on page 2.

If you’re writing a scientific or technical text, the rule is to write out numbers between one and nine, using numerals for 10 and above. Unless the numbers are measured quantities.

• ex: The car traveled at 50 kph.

Above all, be consistent

I'll be honest, though. In the long run, it probably doesn't matter if you choose to spell out a number or use the numeral. What matters is being consistent. There's nothing worse than having a mix of numbers and words all within the same paragraph.

For example, if you're talk about a range of ages, use either numbers or words.

• ex: I work with everyone from the age of five to the age of seventy.

• or: I work with everyone from the age of 5 to the age of 70.

• not: I work with everyone from the age of five to the age of 70.

If numbers aren’t you’re thing, even in this context, don’t worry about it! A copy editor will sort through the chaos for you.

To see how a copy editor can help you, click below.