Do You Write Numbers in APA Format? A Comprehensive Guide

The question of how to format numbers in APA Style can seem daunting, but it’s really about clarity and consistency. This guide breaks down the rules, provides examples, and helps you master the nuances of number formatting in your academic writing. Let’s dive in!

Understanding the Basics: When to Spell Out Numbers

APA Style is primarily concerned with readability. The general guideline for numbers is this: spell out numbers from zero to nine, and use numerals for numbers 10 and above. This rule applies to most situations, but there are exceptions.

Exceptions to the Rule: When Numerals Are Always Used

There are several scenarios where you should always use numerals, regardless of the number’s value. Keeping these in mind will ensure your writing adheres to APA guidelines.

  • Numbers that precede units of measurement: For example, “3 grams,” “5 meters,” “10 years.”
  • Numbers that represent scores or points on a scale: For example, “a score of 7 on the anxiety scale.”
  • Numbers that represent mathematical or statistical functions, fractions, ratios, percentages, and percentiles: For example, “multiplied by 2,” “a ratio of 2:1,” “25% of the sample.”
  • Numbers that represent dates, times, ages, scores, sums of money, and points on a scale: For example, “October 12, 2023,” “4:00 p.m.,” “a 5-year-old child,” “$100.”
  • Numbers that express a specific place in a series: For example, “the 3rd chapter,” “Group 2.”
  • Numbers that refer to a specific place in a table, figure, or list: For example, “Table 4 shows…”

Examples of Number Usage in Sentences

Let’s look at some examples to illustrate the principles:

  • “The study included six participants.” (Spelled out because it’s under 10 and doesn’t fall under the exceptions)
  • “The participants were, on average, 25 years old.” (Numeral because it’s an age)
  • “The researchers found a 3:1 ratio of males to females.” (Numeral because it’s a ratio)
  • “The results are presented in Table 2.” (Numeral because it refers to a table)

Formatting Large Numbers: Clarity and Readability

When dealing with large numbers, APA Style provides guidelines for clarity. Use numerals for numbers 10 and above, even at the beginning of a sentence. For numbers in the millions or billions, you can combine numerals and words to enhance readability.

Using Commas and Spaces

  • Commas: Use commas to separate thousands, millions, and billions (e.g., 1,000, 10,000, 1,000,000).
  • Combining Numerals and Words: You can use a combination of numerals and words for very large numbers. For example, instead of writing 1,500,000, you could write 1.5 million.

Examples of Large Number Formatting

  • “The study involved 1,250 participants.”
  • “The company earned $2.5 million in revenue.”
  • “The population of the city was approximately 1.8 million.”

Decimal Points and Fractions: Precise Representation

Accurate representation of decimal points and fractions is vital in APA Style.

Formatting Decimal Numbers

  • Use a zero before the decimal point for numbers less than one: For example, write “0.75” not “.75.”
  • Round numbers to an appropriate number of decimal places: The number of decimal places to include depends on the data and the context, but generally, two to three decimal places are sufficient.

Formatting Fractions

  • Spell out fractions if they stand alone: For example, “one-half” or “two-thirds.”
  • Use numerals for fractions when they are next to a whole number: For example, “2 1/2” or “3 3/4.”

Examples of Decimal and Fraction Usage

  • “The correlation coefficient was 0.85.”
  • “The probability value was 0.001.”
  • “The participants completed one-half of the task.”
  • “The solution contained 2 1/2 cups of water.”

Numbers in Statistical Reporting: Precision is Key

Statistical reporting demands precision. Adhere to specific formatting guidelines for statistical values.

Reporting Statistical Values

  • Italicize statistical symbols: For example, M, SD, t, F, p.
  • Report p values to two or three decimal places: Be precise and avoid unnecessary detail.
  • Use the correct format for confidence intervals: For example, “95% CI [0.10, 0.30].”

Examples of Statistical Formatting

  • “t(28) = 2.50, p = .017”
  • “M = 7.50, SD = 1.25”
  • “The 95% confidence interval for the mean difference was [0.10, 0.30].”

Numbering in Tables and Figures: Consistent Labeling

Consistency is crucial when labeling tables and figures.

Table and Figure Numbering

  • Use Arabic numerals: For example, Table 1, Figure 2.
  • Provide a clear and concise title for each table and figure.
  • Place the table number and title above the table.
  • Place the figure number and title below the figure.

Examples of Table and Figure Labels

  • Table 1 Descriptive Statistics
  • Figure 2 Mean Scores on the Anxiety Scale

Dates, Times, and Ages: Specific Formatting

APA Style dictates specific formats for dates, times, and ages.

Formatting Dates

  • Use the month-day-year format: For example, “October 26, 2023.”
  • Do not use ordinal numbers (e.g., 1st, 2nd, 3rd) for the day of the month.

Formatting Times

  • Use the 12-hour clock with a.m. and p.m.: For example, “2:00 p.m.”
  • Use the 24-hour clock in some specific cases: Such as in scientific reports or when precise time is critical.

Formatting Ages

  • Use numerals for ages: For example, “a 25-year-old participant.”

Examples of Date, Time, and Age Usage

  • “The study was conducted on November 15, 2023.”
  • “The meeting will begin at 10:00 a.m.”
  • “The average age of the participants was 30 years.”

Consistency is King: Maintaining Accuracy

The most important aspect of number formatting in APA Style is consistency. Once you’ve established your formatting rules, stick to them throughout your entire paper.

Proofreading and Editing

  • Carefully proofread your entire paper for number formatting errors.
  • Use a style checker to help identify inconsistencies.
  • Have a peer review your paper for accuracy.

Avoiding Common Mistakes

  • Inconsistently spelling out numbers or using numerals.
  • Using incorrect formatting for statistical values.
  • Failing to use a zero before the decimal point.
  • Confusing a.m. and p.m.

Numbers and Units of Measurement: Specific Guidelines

When working with units of measurement, adhere to specific guidelines.

Formatting Units of Measurement

  • Always use numerals with units of measurement: For example, “10 kg,” “5 cm.”
  • Use standard abbreviations for units of measurement: For example, “g” for grams, “m” for meters, “s” for seconds.

Examples of Units of Measurement

  • “The sample weighed 15 g.”
  • “The distance was 20 m.”
  • “The reaction took 30 s.”

When to Use Words and Numerals in Combination

Occasionally, you may need to combine words and numerals for clarity.

Combining Words and Numerals

  • In general, try to avoid combining words and numerals within a single number: For example, write “1,250” instead of “one thousand two hundred fifty”.
  • You might combine words and numerals for very large numbers to enhance readability: For example, “2.5 million.”

Examples of Combining Words and Numerals

  • “The company had over $1.5 million in sales.”
  • “The study included approximately 100 thousand participants.”

Numbers in Headings, Titles, and Abstracts: Special Considerations

Headings, titles, and abstracts have specific formatting considerations.

Formatting in Headings and Titles

  • Capitalize the first word and all major words in the title and headings.
  • Follow APA guidelines for spelling out numbers or using numerals.

Formatting in Abstracts

  • Use numerals for numbers in the abstract.
  • Follow the general APA guidelines for number formatting.

Examples of Usage

  • Title: The Effects of 5 Days of Exercise on Cognitive Function
  • Heading: Results: 10 Participants Completed the Study
  • Abstract: The study included 20 participants…

FAQs about Number Formatting in APA Style

  • Can I start a sentence with a numeral? Yes, but only if it’s an exception (e.g., when referring to a date or a specific amount of money). Otherwise, rewrite the sentence.
  • Are there any exceptions for ordinal numbers? No, APA does not use ordinal numbers (1st, 2nd, 3rd).
  • How do I handle numbers that are close together in a sentence? To avoid confusion, rephrase the sentence to separate the numbers or spell out one of them.
  • What about using Roman numerals? Roman numerals are typically not used in APA Style.
  • Where can I find a comprehensive guide to APA Style? The Publication Manual of the American Psychological Association is the definitive resource.

Conclusion: Mastering APA Number Formatting

Following these guidelines for number formatting in APA Style will improve the clarity and professionalism of your academic writing. Remember to prioritize readability, be consistent, and refer to the APA Publication Manual for any specific questions. From spelling out numbers under ten to accurately reporting statistical values, mastering these rules is essential for effective communication in academic and scientific contexts. By paying close attention to detail and practicing these rules, you can ensure that your writing is both accurate and easy to understand.