Kathleen Neal, PhD, RN
Writer’s Camp Counselor
Take a few minutes to learn the rules about numbers for style manuals.
American Psychological Association (APA) and American Medical Association (AMA) formatting rarely pops up in “fun highlights” of anyone’s day. Getting back edits marked with “Numbers wrong here,” “Does this follow7th Edition APA Guidelines in Section 6?” or the dreaded “No way…” comments can feel gut‑wrenching. You can make the process lighter: think of style manual number rules like answering Final Jeopardy—clear, precise, and hopefully with no agonizing second‑guessing.
If you report research or share published data, numbers are your constant companions. They support credibility, clarity, and consistency. The 7th edition of the APA manual (Section 6.32–6.35) sets out exact rules so your reader focuses on your content, not your formatting.
General Rule: Words vs. Numerals
- Spell out numbers zero through nine (e.g. three, nine).
- Use numerals for 10 and above (e.g. 10, 42.).
That’s easy—until exceptions sneak in.
Exceptions: When Numerals Win (Even Below 10)
APA states always use numerals—even for numbers under 10—when they represent:
- Time, dates, ages (She’s 5 years old, Arrived at 3:15 pm)
- Placement in a sequence (Chapter 4, Table 2)
- Scores or scale points (averaged 6 on a 7‑point scale)
- Exact sums of money ($5)
- Mathematical or statistical expressions (n = 275, 5% of the sample, ratio of 2:1)
- Units of measurement (5 cm, 2.45 ft)
- Numbers in the abstract (always use numerals for brevity).
Exceptions: When Words Win (Even Above 10)
Spell out numbers in these cases:
- When a number starts a sentence, heading, or title (Twenty‑nine people…)
- When expressing a common fraction (two‑thirds of the sample.)
- For universally accepted phrases (the Twelve Apostles, the Five Pillars of Islam).
Combo Cases for Clarity
When two numbers appear side‑by‑side, APA recommends a mix of words and numerals to avoid confusion:
- three 5-point scales
- ten 7-point scales
- twelve 16 year olds
Hacks to Avoid Editor Panic
Before you hit “submit draft,” quickly scan for these tricky cases. If you end on a clause with a number—like “The fence posts are 6.25 feet apart”—ask yourself: does that represent measurement? If yes: numeral(s). If no obvious rule applies: rewrite.
Remember that inconsistent formats—like “nine participants and 12 eligible”—draw eyes during the edit process. How should you handle this? There are several different options you can consider.
- Leave as is. Technically this is correct, although it is kind of irritating. And, it can be argued that as a series, the numbers should be consistent, and this isn’t.
- Change nine to 9, like this: “9 participants and 12 eligible.” As an aside, this would be correct in AMA style.
- Change it so the numbers aren’t in a series: “There were nine participants selected from the pool of 12 eligible participants.” (Note, however, that “participants” is used twice in the sentence and that’s not ideal.)
- Another rewrite: “There were nine participants recruited for the study from a sample of N = 12 eligible individuals.”
- And another rewrite: “There were nine participants recruited for the study from a total of 12 individuals who met the eligibility criteria.” You could even turn this into two sentences, if you wanted: “There were nine participants recruited for the study. A total of 12 individuals met the eligibility criteria in the initial sample.”
Reviewers often flag numbers that don’t follow standard patterns; APA consistency lets them focus on your research, not your formatting questions.
What About AMA Style?
About 30% of journals use AMA 11th Edition style, including The Writer’s Camp Journal, so a few words on how that style guide handles numbers are in order. Fortunately, the rules are very similar with one big exception: numerals are always used, even below 10. The exceptions are the same: Spell out the numeral:
- When the number begins the sentence or title.
- For common fractions.
- For ordinals: first through ninth.
- The number is in quotations or titles of works cited: “The Mystery Disease that Afflicted Six Children.”
- One number may be spelled out, if the sentence requires multiple numbers to be placed next to each other. e.g., “If 12 16-year-olds had this reaction…” should be changed to “If twelve 16-year-olds…”
Conclusion
Numbers are small but mighty—minor things that can trip up a paper’s polish if misused. APA 7th Edition lays out a clear framework: spell out one through nine, use numerals for 10 and above, with well-defined exceptions. AMA is mostly the same, with one difference (which is easy to remember): use numbers 1 through 9 and above 10. The exceptions are the same. It may feel less fun than writing content but mastering these rules will save you—and your reviewer—time, second guesses, and editorial no‑way comments.
Think of APA and AMA number rules as a friendly Jeopardy opponent: know the categories, choose your phrasing, stay consistent—and you’ll hit the buzzer before the editor does. Format with confidence, clarity, and your headache will shrink to nearly zero.
References
APA 7th Edition Sections 6.32–6.35 are the formal authority—but resources like Purdue OWL, and university writing guides provide clear, practical summaries on numbers, measurement, time, fractions, percentages, abstracts, and more.
Author: Kathleen Neal
Reviewed and Edited by: Leslie H. Nicoll
Copyright © 2025 Writer’s Camp and Kathleen Neal. CC-BY-ND 4.0
Citation: Neal K. Writing style and numbers: Turning a headache into a (Jeopardy-style) game. The Writers Camp Journal, 2025; 1(2):20. doi:10.5281/zenodo.17219447
This is so helpful. thank you