Style Guide

Numbers and numerals guide

​Writing out numbers or numerals

  • In general, write out numbers zero through nine. Use numerals for numbers 10 and above. Common exceptions include age, weight, monetary amounts, temperature, page numbers, scores and percentages.

  • Write out any number that begins a sentence.

  • Write out ordinal numbers (a number that indicates rank) under 10; use numerals for ordinal numbers 10 and above. 
    Example: Drowning is the third leading cause of death of children ages 10-16. In 1965, it ranked 15th.

  • Use numerals for each number when two or more numbers appear in a sentence and 1 of them is 10 or larger.
    Example: Last month, 8 of the 16 geothermal sites were evaluated.

  • Use numerals (not words) until one million.
    Examples: 3,000 (not 3 thousand) 3 million (not 3,000,000)

  • Use Roman numerals (I, V, X, L, C, D and M) for wars and to show personal sequence for animals and people (World War II, Pope John Paul VI, King George III).

Writing out or using numeral for fractions

  • Write out simple frac​tions.

  • Use numerals for mixed fractions.

  • Write out fractions that are followed by a, of, or of an.
    Example: Almost one-fourth of the children in our community are overweight or obese.

  • Use numerals in fractions that are followed by a unit of measure.
    Example: The greenway segments are at least 4¼ miles apart.

  • Spell out amounts less than 1, using hyphens between the words: one-third, seven-eighths, etc. Use figures for precise amounts larger than 1.
    Example: According to the National Weather Service, we are 6 ¾ inches behind in rainfall.

Writing out or using the symbol for percent

  • ​Express percentages in numerals.

  • Use the percent symbol (%) or the word percent consistently within a document. Do not put a space between the number and the percent symbol (%).

Using numbers with currency

  • ​Write out the word "cents" when writing about cents only (when not writing about dollars). 
    Example: It costs 15 cents to recycle these items.

  • If the number expressing an amount of money is spelled out, so are the words dollars or cents. If numerals are used, they are accompanied by the symbol $ or ¢. 
    Example: The average savings was $1 million.

Writing out or using numerals for dates and years

  • Use numerals to refer to a span of years, but omit the first two digits of the second number. 
    Example: Changes apply to the 2001-07 mechanical code standards.

  • Don't abbreviate the year. Use all four digits; don't omit the first two digits. 
    Example: New investment in clean energy sources worldwide soared in 2008.

  • Write out the number associated with a century if the number is under 10. Use lowercase.

  • Write out decades in lowercase or use numerals. If you use numerals, do not use the apostrophe between the numerals and the "s".
    Example: Staff levels for the program are similar to those in the early '90s. 

Using commas in numerals of four digits or more

  • Use commas between groups of three digits, starting from the right, to show thousands, millions, etc. 
    Example: More than 2,000 pounds of materials were recycled. Nearly 200,000 pounds are recycled annually.

Using decimals

  • Use a zero before a decimal point if there is no value in the first place to the left of the decimal. 

  • Round to a whole number unless it is important to show the exact number.

  • Omit zeros after a decimal point unless they indicate exact measurement and the audience needs to know the level of significance.

Formatting phone numbers

  • Use hyphens between number groups so that a user can dial the number from a mobile device. Spaces and/or dots between number groups don't work in mobile. 

  • Because area codes must be dialed in most cases, they should not be placed inside parentheses.
    Example: 704-336-7600​