You may have noticed a theme when it comes to the English language: most rules are not completely standardized. This (somewhat frustrating) fact is especially true when it comes to spelling out numbers.
Should you write them out in words or leave them as numerals? To write numbers properly, you will have to identify potential differences between major style guides (such as MLA, APA, and Chicago, to name a few) because these guides often outline different rules for using numbers in writing.
To make it easier, let's use an example. Say you're working on a paper evaluating the importance of the local public library in your community.
The document will make use of small numbers, large numbers, decades, and statistics.
Thankfully, when using numbers in writing, you can count on a few conventions that apply to most situations; just be sure to consult your specific style guide if one has been assigned.
Small and Large Numbers
A simple rule for using numbers in writing is that small numbers ranging from one to ten (or one to nine, depending on the style guide) should generally be spelled out. Larger numbers (i.e., above ten) are written as numerals.
For example, instead of writing, “It cost ten-thousand four-hundred and sixteen dollars to renovate the local library,” you would write, “It cost $10,416 to renovate the local library.”
The reason for this is relatively intuitive. Writing out large numbers would not only waste space but could also be a major distraction to your readers.
Beginning a Sentence
- Here is a rule that you can truly rely on: always spell out numbers when they begin a sentence, no matter how large or small they may be.
- Incorrect: 15 new fiction novels were on display.
- Correct: Fifteen new fiction novels were on display.
- If the number is large and you want to avoid writing it all out, rearrange the sentence so that the number no longer comes first.
- Revised: There were 15 new fiction novels on display.
Whole Numbers vs. Decimals
Another important factor to consider is whether you are working with a whole number or a decimal. Decimals are always written as numerals for clarity and accuracy.
To revisit our library example, perhaps circulation statistics improved in 2015. If a number falls in the range of one to ten and is not a whole number, it should be written as a numeral.
Incorrect: The circulation of library materials increased by four point five percent in 2015.
Correct: The circulation of library materials increased by 4.5% in 2015.
When two numbers come next to each other in a sentence, be sure to spell out one of these numbers. The main purpose of this rule is to avoid confusing the reader.
- Incorrect: There were 12 4-year-old children waiting for the librarian to begin story time.
- Correct: There were twelve 4-year-old children waiting for the librarian to begin story time.
- Correct: There were 12 four-year-old children waiting for the librarian to begin story time.
Decades and Centuries
- Decades or centuries are usually spelled out, especially if the writing is formal.
- Incorrect: The library was built in the '50s.
- Correct: The library was built in the fifties.
If you are referring to a specific year (e.g., 1955), use the numeral.
Always strive for consistency, even if it overrides a previous rule. For example, if your document uses numbers frequently, it is more appropriate for all numbers to remain as numerals to ensure that usage is uniform throughout. Similarly, if a single sentence combines small and large numbers, make sure that all the numbers are either spelled out or written as numerals.
Incorrect: The library acquired five new mystery novels, 12 new desktop computers, and 17 new periodicals.
Correct: The library acquired 5 new mystery novels, 12 new desktop computers, and 17 new periodicals.
Let's complicate things a bit, shall we?
If your work must follow the rules of a specific style guide, understand that they all have rules for spelling out numbers that may differ slightly from the rules listed above.
For example, MLA style indicates that writers may spell out numbers if they are not used too frequently in the document and can be represented with one or two words (e.g., twenty-four, one hundred, three thousand). APA style advises that common fractions (e.g.
, two-thirds) be expressed as words. A number of specific rules for spelling out numbers are outlined in section 9.1 of the Chicago Manual of Style.
- Your ultimate authority will always be a style guide, but in the absence of one, following the rules outlined above will help you be consistent in your use of numbers in writing.
- Image source: Martin Vorel/Pexels.com
When Should I Spell Out Numbers?
It is generally best to write out numbers from zero to one hundred in nontechnical writing. In scientific and technical writing, the prevailing style is to write out numbers under ten. While there are exceptions to these rules, your predominant concern should be expressing numbers consistently.
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- Numbers can disrupt readability in a paragraph, so for most writing purposes, it is best to flex those fingers and type out numbers less than 101 as fully spelled words.
Sophie said there are ninety-nine reasons why she adores Justin Bieber, not ten.
According to census records, there were 53,364 people over the age of one hundred in the U.S. in 2010.
When writing out numbers between forty and forty-nine, be sure to remember that forty has no u in it (this is a common spelling error).
The rules demonstrated in the examples above are simply rules of thumb and there are exceptions to them. For example, round numbers such as hundreds, thousands, or hundred thousands should be written out in full. Numbers that are not conveniently round will read better written as numerals.
It was said that there were five loaves and two fish to feed five thousand men.
This year’s parade brought in 123,675 attendees.
When a number begins a sentence, that number should always be spelled out. That said, writers often choose to restructure their sentences when the numbers become cumbersome for the reader.
5 finalists will qualify for the next round of the competition.
Five finalists will qualify for the next round of the competition.
Seventeen seventy-six was the year America became a nation.
In 1776, America became a nation.
Spelling Out Numbers in Technical, Scientific, and Complex Writing
Scientific and technical journals, and even news reports, often adhere to the rule that only numbers less than ten should be written out in full, except when fractions or decimals are involved. This can be a sensible approach to ensuring the readability of texts that refer to numbers and figures frequently.
Numbers – Microsoft Style Guide
- 5 minutes to read
in your use of numbers. When you write about numbers used in
examples or UI, duplicate them exactly as they appear in the UI. In
all other content, follow the guidelines below.
Numerals vs. words
- In body text, spell out whole numbers from zero through nine, and use numerals for 10 or greater. It's OK to use numerals for zero through nine when you have limited space, such as in tables and UI.
10 screen savers
Spell out zero through nine and use numerals for 10 or greater for days, weeks, and other units of time.
If one item requires a numeral, use numerals for all the other items of that type.
One article has 16 pages, one has 7 pages, and the third has only 5 pages.
Microsoft Inspire is only one month and 12 days away.
When two numbers that refer to different things must appear together, use a numeral for one and spell out the other.
fifteen 20-page articles
Don't start a sentence with a numeral. Add a modifier before the number, or spell the number out if
you can't rewrite the sentence. It's OK to start list items with numerals—use your judgment.
More than 10 apps are included.
Eleven apps are included.
Use numerals in these situations.
|Measurements of distance, temperature, volume, size, weight, pixels, points, and so on—even if the number is less than 10.||3 feet, 5 inches 1.76 lb 80 × 80 pixels 0.75 grams 3 centimeters 3 cm|
|A number the customer is directed to enter.||Enter 5.|
|A round number of 1 million or more.||7 million|
|Dimensions. Spell out by, except for tile sizes, screen resolutions, and paper sizes. For those, use the multiplication sign (×). Use a space before and after the multiplication sign.||10-foot cable 4 × 4 tile 8.5″ × 11″ paper 1280 × 1024|
|Time of day. Include AM or PM. Exception Don't use numerals for 12:00. Use noon or midnight instead. Include the time zone if you're discussing an event, and customers beyond the local time zone may see it. Time stamps in UI and websites usually display local time and date automatically.||10:45 AM 6:30 PM The meeting is at noon. The event starts at 5:00 PM Pacific Time. The date changes at midnight.|
|Percentages, no matter how small. Use a numeral plus percent to specify a percentage. Use percentage when you don't specify a quantity.||At least 50 percent of your system resources should be available. Only 1 percent of the test group was unable to complete the task.A large percentage of system resources should be available.|
|Coordinates of tables or worksheets and numbered sections of documents.||row 3, column 4 Volume 2 Chapter 10 Part 5 step 1|
Commas in numbers
Use commas in numbers that have four or more digits.
Exception When designating years, pixels, or baud, use commas only when the number has five or more digits.
1920 × 1080 pixels
10,240 × 4320 pixels
- 14,400 baud
- Don't use commas in page numbers, addresses, or after the decimal point in decimal fractions.
- 15601 NE 40th Street
Don't use ordinal numbers, such as June first or October twenty-eighth, for dates. Use a numeral instead: June 1, October 28.
Global tip To avoid confusion, always spell out the name of the month. The positions of the month and day vary by country. For example, 6/12/2017 might be June 12, 2017 or December 6, 2017.
Form a negative number with an en dash, not a hyphen:
Hyphenate compound numbers when they're spelled out.
the twenty-first day
Fractions and decimals
- Express fractions in words, as symbols, or as decimals, whichever is most appropriate.
- In tables, align decimals on the decimal point.
- Add a zero before the decimal point for decimal fractions less than one, unless the customer is asked to enter the value.
- Don't use numerals separated by a slash to express fractions.
When an equation occurs in text, it's OK to use a slash between the numerator and the denominator. Or, in Microsoft Word, go to the Insert tab, and select Equation to format the equation automatically.
½ + ½ = 1
- Hyphenate spelled-out fractions. Connect the numerator and denominator with a hyphen unless either already contains a hyphen.
one-third of the page
measurements where the unit of measure is spelled out, use the plural
form when the quantity is a decimal fraction. Use the singular form only
when the quantity is 1.
- Always spell out ordinal numbers.
the first row
the twenty-first anniversary
- Don't use ordinal numbers, such as June first, for dates.
- Don't add -ly to an ordinal number, as in firstly or secondly.
Ranges of numbers
- In most cases, use from and through to describe a range of numbers.
from 9 through 17
Use an en dash in a range of pages or where space is an issue, such as in tables and UI. For example, 2016–2020 and pages 112–120.
Use to in a range of times. For example, 10:00 AM to 2:00 PM.
- Don't use from before a range indicated by an en dash, such as 10–15.
In general, don't abbreviate thousand, million, and billion as K, M, and B. Spell out thousand,
million, and billion, or use the entire number.
Fabrikam, Inc., employs more than 65,000 people.
Total cost to the enterprise: 300,000 hours and $30 million per year
In UI, avoid the abbreviations unless space is too limited to spell out the number.
Global tip Machine translation might not translate these abbreviations correctly. Also, an abbreviated form
might not be available or might be longer in the target language, so allow space for expansion in localized content.
If you must use the abbreviations, follow these guidelines:
- Capitalize K, M, and B.
- Don't put a space between the number and the abbreviation.
- Use the decimal form of a number only if it really will save space. In particular, avoid the use of a decimal
with K—8.21K has the same number of characters as 8,210.
Date and time term collection
Units of measure term collection
Bits and bytes term collection
Dashes and hyphens
Dashes and hyphens
Numbers: Writing Numbers // Purdue Writing Lab
This section discusses numbers, how to write them correctly, and when to use numerical expressions instead.
Although usage varies, most people spell out numbers that can be expressed in one or two words and use figures for numbers that are three or more words long. Note: If you are using a specific citation style, such as MLA or APA, consult the style manual for specific formatting instructions.
- over two pounds
- six million dollars
- after thirty-one years
- eighty-three people
- after 126 days
- only $31.50
- 6,381 bushels
- 4.78 liters
- Here are some examples of specific situations:
- Days and Years
- December 12, 1965 or 12 December 1965
- in 1900
- in 1971-72 or in 1971-1972
- the eighties, the twentieth century
- the 1980's or the 1980s
- Time of Day
8:00 A.M. (or) a.m. (or) eight o'clock in the morning
4:30 P.M. (or) p.m. (or) half-past four in the afternoon
- 16 Tenth Street
- 350 West 114 Street
- Identification Numbers
- Room 8
- Channel 18
- Interstate 65
- Henry VIII
- Page and Division of Books and Plays
- page 30
- chapter 6
- in act 3, scene 2 (or) in Act III, Scene ii
- Decimals and Percentages
- a 2.7 average
- 13.25 percent (in nonscientific contexts)
- 25% (in scientific contexts)
- .037 metric ton
- Large Round Numbers
- four billion dollars (or) $4 billion
- 16,500,000 (or) 16.5 million
- Repeat numbers in commercial writing.
- The bill will not exceed one hundred (100) dollars.
- Use numerals in legal writing.
The cost of damage is $1,365.42.
- Numbers in series and statistics should be consistent.
- two apples, six oranges, and three bananas
- NOT: two apples, 6 oranges, and 3 bananas
- 115 feet by 90 feet (or) 115' x 90'
- scores of 25-6 (or) scores of 25 to 6
- The vote was 9 in favor and 5 opposed
- Write out numbers beginning sentences.
- Six percent of the group failed.
- NOT: 6% of the group failed.
- Use a combination of figures and words for numbers when such a combination will keep your writing clear.
Unclear: The club celebrated the birthdays of 6 90-year-olds who were born in the city. (may cause the reader to read '690' as one number.)
Clearer: The club celebrated the birthdays of six 90-year-olds who were born in the city.
Numbers in academic writing
The rules for using numbers in academic writing vary among academic disciplines. The conventions described here are for non-technical academic prose where numbers are not a significant focus.
Scientific and technical writing will have their own conventions and students should consult a manual dedicated to those standards.
The main rules about the use of numbers in standard academic writing are about:
Grammar checkers will not help you with the acceptable presentation of numbers in academic writing. You need to know and use the conventions for writing numbers correctly when you are writing and proofreading your work.
When to write numbers in words
Write in words all numbers under one hundred, rounded numbers and ordinal numbers
For general academic writing, you need to write these numbers in words: all numbers under one hundred (e.g. ninety-nine) rounded numbers (e.g. four hundred, two thousand, six million) and ordinal numbers (e.g. third, twenty-fifth). Exceptions: see below, When to write numbers in digits
- The country had been at war for twenty-five years.
- Over four hundred soldiers were sent to the war zone.
- The thirty-eighth battalion was sent to the war zone for the fourth time.
Write in words numbers beginning a sentence
Either write the number in words or, if that’s awkward, then rewrite the sentence to avoid beginning the sentence with a numeral. Exception: You can begin a sentence with a date.
- INCORRECT: 130 student volunteers joined the university peace mission.
- CORRECT: One hundred and thirty student volunteers joined the university peace mission.
- INCORRECT: 75 percent of the rental properties were occupied by students.
- CORRECT: Students occupied 75 percent of the rental properties in the town.
- CORRECT: 2008 was a good year to commence university studies.
Write in words approximate numbers and some times of the day
In non-technical academic writing, write in words the number for approximate figures (including fractions) and for full, half and quarter hour times.
- about half the students; a quarter of the university; four times as often; hundreds of times
- six o’clock, half past six, quarter past seven, quarter to nine, midday, midnight
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When to write numbers in digits
|Numbers above 100||Use digits.||I counted 3968 books on the shelves.|
|Money||Use digits for exact amounts but digits and words for rounded and large amounts.||$24.28 (exact amount); 98 dollars; $15 million (rounded and large amounts)|
|Measurements||Use digits with a measurement symbol.||32 °C or 32 degrees centigrade; 6 cm or 6 centimetres|
|Decimals||Give exact amounts in digits.||0.45 not .45; 2.36|
|Surveys||Write survey results in digit form.|