# Writing numbers: words and numerals

Numbers can be written either as words (e.g., one hundred) or numerals (e.g., 100). In this article we follow the guidelines of APA Style.

In general, words should be used for numbers from zero through nine, and numerals should be used from 10 onwards. This is true for both cardinal numbers (e.g., two, 11) and ordinal numbers (e.g., second, 11^{th}). However, there are some important exceptions to this rule.

Note that other style guides, such as Chicago and Harvard, address numbers differently (for example, in Chicago, you use words for numbers up to 100). Regardless of what style guide you follow, the most important thing is to be consistent in how you treat numbers throughout your document.

## 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 larger than 10.

###### Examples:

The samples measured ** 7** cm in diameter.

*(“cm” is a unit of measurement)*

However, only ** 3** of the

**were usable.**

__12__*(“3” is being grouped with “12”)*

*But: *These ** three** samples were subjected to further testing.

Use words for any number that is used to start a sentence, with the exception of years.

###### Examples:

** Seventy-two thousand** ink cartridges are sold every day.

** Nineteenth-century** novels often feature complicated plot lines.

*But:* ** 2008** saw record olive crops throughout the Mediterranean.

Use words for common fractions and set expressions.

###### Examples:

According to the survey, ** two thirds** of the employees are dissatisfied.

Understanding the ** Five Pillars of Islam** is a critical first step.

The ** Fourth of July** is traditionally marked by a firework display.

## Writing percentages

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

###### Example:

According to the report, ** 45%** of the workforce is employed in the service sector. Only

**currently work in agriculture.**

__6%__The main exception is if you are using a percentage to begin a sentence. In this case, use words to express the entire percentage.

###### Example:

** Thirteen percent** of the patients reported that their symptoms improved after taking the experimental drug.

## Reporting statistical results that include numbers

If your paper includes quantitative research, you probably have data to report. Statistics, mathematical functions, ratios, and percentages are all written using numerals. This is true regardless of whether 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). - If a value has the potential to exceed 1.0, use the leading zero. If a value can never exceed 1.0, do not use the leading zero.
- Italicize values that are not Greek letters (such as
*M*,*SD*,*p*, and*F*). - Include spaces before and after =, >, and <.

###### Examples:

The average IQ of the participants was relatively high (*M* = 137.33, *SD *= 4.54).

The results of the second test were statistically significant, *t*(12) = 4.11, *p* < .05.

## Writing numbers that are accompanied by measurements

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

###### Examples:

Each patient received ** 5 mg** of the experimental drug.

The tallest participant was ** 2.03 m**.

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

###### Examples:

The final score of ** Ghana 2, Brazil 1** did not represent a decisive victory.

Children under ** 8 years** receive a

**discount.**

__$50__*But:* Most girls start reading when they are ** about five years** old. (“about” makes the number imprecise)

## Writing long numbers

Longer numbers follow specific rules:

- Use a period to indicate a decimal point.
- Starting with 1,000, use commas to separate every three digits.
- Starting with a million, use a combination of numerals and words.
###### Examples:

The region has an average of

doctors for every__43.75__people.__10,000__Some predict that the number of users will reach

by 2020.__2 billion__

## Consistency may not be obvious

One of the main reasons why writing numbers is complicated is that consistently applying the rules may lead to a text that actually seems very *in*consistent. Consider the following paragraphs:

###### Examples:

At about the age of ** seven**, the girl’s height was

**m. This placed her in the**

__1.47__**percentile, although her weight placed her in the top**

__fifth__**of her class. By the time she was**

__7%__**years old, she was taller than**

__9__**of the boys in her year.**

__half__**years later, she was still ranked**

__Five__**.**

__15__^{th}** Thirteen thousand** viewers watched the performance of Shakespeare’s

__Twelfth__*Night*from the park, while another

**watched from the surrounding buildings and**

__2,000__**watched it on television. As**

__1.2 million__**out of every**

__1__**residents saw at least part of the play, this**

__11__**event can definitely be considered a success.**

__one__These texts may look awkward because so many different number formats have been used, but don’t be deceived – the above guidelines have all been followed.

If you are not required to strictly follow a particular style (such as APA), you may have some flexibility to modify the guidelines presented in this article. Just be sure to apply any modifications you make throughout your entire document.

## 2 comments

## Caroline

May 10, 2019 at 9:16 PMThe information has assisted me very much

## Emma

February 9, 2019 at 3:28 PMWhat about "hours/h" and "minutes/min"? A sentence starting with Twenty-four hours and later in a sentence, where it refers to the same thing, should it be 24 h? Thanks.