Writing Numbers in Academic Writing
Knowing when to write a number as a word (five) or a numeral (5) is an important academic-style skill.
The basic rule: use words for zero to ten, and numerals from 11 onwards (the same applies to ordinals: first … tenth, then 11th). Referencing systems vary — APA uses words for zero to nine; Chicago uses words up to one hundred.
| Use words | Use numerals |
|---|---|
| zero to ten (three, seven) | 11 and above (24, 350) |
| a number that begins a sentence | measurements (6 kg, 3 cm) |
| large round numbers (7 billion) | currency, percentages (75%), ratios (3:1) |
| dates, times, decimals, statistics |
Exceptions: always use words when a number starts a sentence (Fifty respondents agreed…), but use numerals when large and small numbers are combined (2 respondents in the first category, and 22 in the second).
Other points: be consistent (don't mix 7bn and 5 billion); use commas every three digits (5,500); use a hyphen with no space for ranges (30%–50%); write fractions as numerals (2/3) or hyphenated words (two-thirds).
Tip: Remember the dividing line at eleven: words below, numerals from 11 up — unless an exception (sentence start, measurements, currency, percentages) applies.
Common mistake: Starting a sentence with a numeral ("50 respondents agreed…"). Use words, or rewrite so the number is not first.
✏️ Test Yourself
1. "There are ___ main reasons." (3)
2. A measurement like 6 kg
3. A number at the start of a sentence
4. A percentage like 75%
📒 Words to learn
Meaning — uselessness as a consequence of having no practical result
“She didn't want to face the futility of her situation.”
Meaning — work hard
“I toiled in order to defeat him.”
Meaning — a person who amuses others by ridiculous behavior
“I have never seen such a buffoon like him.”
Meaning — Very different from
“My opinion is far cry from yours.”
Meaning — When someone understands the situation well
“I’m on the ball now.”