Do You Write Out Numbers in APA Style? A Comprehensive Guide

The world of academic writing, especially when adhering to the American Psychological Association (APA) style, can feel like navigating a complex maze. One of the trickiest turns involves numbers: when do you spell them out, and when do you use numerals? This article will be your detailed map, guiding you through the specific rules of writing out numbers in APA style, ensuring your papers are both accurate and professional.

Understanding the Fundamentals of APA Number Style

Before diving into the nitty-gritty, it’s crucial to grasp the basic principles governing number usage in APA style. Consistency is key. The guidelines are designed to promote clarity and readability, making your work easier for your audience to understand. Deviating from these rules can create confusion and detract from the impact of your research. Think of it as a language: following the grammar rules ensures effective communication.

The General Rule: When to Spell Out Numbers

Generally, you should spell out numbers in APA style under the following circumstances:

  • Numbers from zero to nine: This is the most fundamental rule. Write out numbers like “one,” “two,” “three,” and so on.
  • Numbers that begin a sentence: Always spell out a number if it starts a sentence. For example, write “Twenty participants were selected…” rather than “20 participants were selected…”
  • Common fractions: Fractions such as “one-half,” “two-thirds,” and “three-quarters” are typically written out.
  • Universal phrases and common expressions: Certain phrases, like “a hundred years ago” or “in one fell swoop,” should be written out.
  • Numbers in titles of tables and figures: In the title of a table or figure, spell out numbers.

Exceptions to the Rule: When to Use Numerals

While the general rule favors spelling out numbers, several exceptions exist where numerals are preferred:

  • Numbers of 10 and above: Use numerals for numbers 10 and higher. For instance, write “12 participants” instead of “twelve participants.”
  • Numbers that precede units of measurement: Use numerals when a number is followed by a unit of measurement (e.g., 3 cm, 15 kg, 6 years).
  • Numbers representing statistical or mathematical functions: Numerals are used for statistical data, such as mean scores (M = 2.5), standard deviations (SD = 1.0), and percentages (75%).
  • Numbers representing scores, points, or degrees: If you’re discussing scores on a test, points earned, or degrees of temperature, use numerals.
  • Numbers indicating time, dates, ages, scores, and points on a scale: For specific dates (e.g., March 15, 2023), ages (e.g., 2 years old), scores (e.g., a score of 95), or points on a scale (e.g., a rating of 4 on a 5-point scale), use numerals.

The nuances of number formatting extend to more complex scenarios. Let’s break down compound numbers and ordinal numbers:

Compound Numbers

Compound numbers (e.g., twenty-one, forty-eight) follow the general rule. Spell out compound numbers that fall under the zero-to-nine range (e.g., “twenty-one,” “ninety-nine”). For compound numbers of 100 and above, use numerals for the hundreds, thousands, and so on, while spelling out the smaller numbers if they fall within the zero-to-nine range (e.g., 123, but “one hundred and seven”).

Ordinal Numbers

Ordinal numbers (e.g., first, second, third) follow the same general rules as cardinal numbers (one, two, three). Spell out ordinal numbers from first to ninth, and then use numerals for tenth and above. For example, you’d write “the first chapter” but “the 10th edition.”

Numbers in Tables and Figures: A Special Case

Tables and figures have their own set of rules for number usage in APA style. Always use numerals for numbers within tables and figures, regardless of their magnitude. This consistency enhances readability and allows for easier data interpretation. The titles of tables and figures, however, follow the standard rules: spell out numbers under ten.

Common Pitfalls to Avoid

Even seasoned writers can stumble. Here are some common errors to watch out for:

  • Inconsistent application of the rules: The most frequent mistake is mixing numeral and spelled-out forms without a clear rationale. Always adhere to the APA guidelines.
  • Over-reliance on numerals: Using numerals for all numbers, even those within the general rule, can make your writing feel less professional.
  • Ignoring the context: Always consider the context of your writing. If a number is part of a statistical calculation, numerals are almost always appropriate.
  • Confusing cardinal and ordinal numbers: Be careful to distinguish between numbers that describe quantity (cardinal) and those that describe order (ordinal).

Practical Examples: Putting the Rules into Practice

To solidify your understanding, let’s look at some practical examples:

  • “The study included three groups of participants.” (Number under 10, spelled out)
  • “There were 15 participants in the experimental group.” (Number 10 or above, numeral)
  • “The participants’ average age was 25 years.” (Age, numeral)
  • “The researcher presented the findings in the second section.” (Ordinal number, spelled out because it’s second)
  • “The table shows 4 different variables.” (Numeral within a table)
  • “The experiment lasted for 6 months.” (Number followed by a unit of measurement)

Refining Your Writing: Resources and Tools

Several resources can help you master APA style number formatting:

  • The Publication Manual of the American Psychological Association: This is the definitive guide. Refer to it for the most accurate and up-to-date information.
  • APA Style websites and online resources: Many websites offer guides, tutorials, and examples to clarify APA style rules.
  • Style checkers: Software like Grammarly (though not specifically APA-focused) can help identify inconsistencies in your number usage.
  • Your professor or academic advisor: Don’t hesitate to ask for clarification if you’re unsure about a particular rule.

Frequently Asked Questions

Here are some frequently asked questions to help clarify any remaining uncertainties:

What if a number falls into two categories simultaneously?

When a number falls into two categories, prioritize the exception. For example, if a number is both 10 or higher and precedes a unit of measurement, use the numeral (e.g., “15 cm”).

Does the rule change based on the type of paper?

The APA style rules remain consistent across all types of academic papers, including research reports, literature reviews, and essays.

Should I use a comma in large numbers?

Yes, use commas for numbers of 1,000 or more (e.g., 1,000, 1,500, 10,000).

What about mixed fractions?

Mixed fractions (e.g., 2 1/2) are generally written as numerals.

Can I use a spell checker to catch errors?

While a spell checker can catch basic spelling mistakes, it won’t always flag APA-specific number formatting errors. You still need to understand the rules and proofread carefully.

Conclusion: Mastering the Art of APA Numbering

Understanding and applying the rules of writing out numbers in APA style is crucial for producing clear, concise, and professional academic writing. This guide has provided a comprehensive overview of the rules, exceptions, and practical applications. By remembering the general rule, understanding the exceptions, and practicing consistently, you can confidently navigate the intricacies of APA number formatting. Your adherence to these standards will not only improve the readability of your work but also demonstrate your commitment to academic rigor and professionalism. Now, go forth and write with clarity and precision!