 ### Numbers in your thesis: Should you use words or numerals?

Even experienced writers find it tricky to decide how to handle numbers within the body of their thesis. To make matters worse, many style guides use very different formats. What is a student to do?

The basic rules

Numbers can be written either as words (e.g., one hundred) or numerals (e.g., 100). The basic rule is to use words for numbers from zero through nine, and then numbers from 10 onwards. This is true for both cardinal numbers (e.g., two, 11) and ordinal numbers (e.g., second, 11th). However, there are some exceptions:

• Use numerals for numbers from zero to nine that are followed by a precise unit of measurement or grouped together with a number that is ≥ 10.
• Use words for any number that is used to start a sentence, with the exception of years.
• Use words for common fractions and set expressions.

Writing percentages

With percentages, the standard is to use numerals and “%” (not “percent”).

The main exception is if you are using a percentage to begin a sentence. In this case, use words to express the entire percentage.

Reporting results that include numbers

If your thesis includes quantitative research, you probably have data to report. Statistics, mathematical functions, ratios, and percentages are all written using numerals. This is true regardless if they are included within a table or as part of the actual text. Keep the following guidelines in mind:

• Report most statistics to two decimal places (such as M = 5.44).
• Report statistics that could never exceed 1.0 to three decimal places (such as p < .001).
• Report percentages and degrees of freedom as whole numbers (such as 73%).
• Italicize values that are not Greek letters (such as MSDp, and F).
• Include spaces before and after =, >, and <.

Writing numbers that are accompanied by measurements

If a number comes immediately before a unit of measurement, use numerals.

Also use numerals for precise ages, times, dates, scores, points on a scale, and amounts of money.

Writing long numbers