Writing Numbers (Part One)
In this lesson and the lesson that follows, we’re going to cover when you should write out numbers as words (twenty) and when you should write numbers as numerals (20). Keep in mind that these rules might differ from the rules used in your workplace, especially if you work in a scientific or technical field. Always consult your company’s style guide if you are unsure whether to write a number as words or use numerals.
Numbers as Written Words
Write out numbers that are one or two words long:
Our company has four locations.
I logged almost one hundred hours on that project.
Use numerals for numbers that would be three or more words long:
Incorrect: I heard that Jan spent two hundred twentyfive hours on the project.
Correct: I heard that Jan spent 225 hours on the project.
Write out all numbers that begin a sentence:
Five thousand people attended the conference.
Seventy percent is equivalent to a “C” grade.
Three employees called in sick today.
Do not start a sentence with a number consisting of three or more words. Rewrite the sentence instead:
Incorrect: One hundred thirtyfive thousand people attended the convention.
Correct: The convention had 135,000 people in attendance.
Write out people’s ages and simple fractions:
Rick’s daughter is nineteen. His son is twentyone.
Cats spend twothirds of their lives sleeping.
However, you should use numerals when a person’s age is over one hundred:
Her grandmother lived to the age of 103.
Do not mix words and numerals when numbers are in a series:
Incorrect: He owns 165 DVDs, seventy video games, and fiftyfive books.
Correct: He owns 165 DVDs, 70 video games, and 55 books.
When two numbers are together, write one number in words and the other number in numerals for clarity:
Susan bought a package of three $20 gift cards.
Ron worked 6 twelvehour days to finish the project by the deadline.
For round numbers larger than one million, use a combination of numerals and words:
There are over 3.9 million people living in the state of Georgia.
The philanthropist donated $1.5 million of his own money to the relief effort.
Do not combine symbols or abbreviations and numbers as written words. Unless you are working in a scientific or technical field, avoid using symbols and abbreviations in formal writing:
Correct  Incorrect  
Numbers as Words  Numerals with
Symbols 
Words with Symbols or Abbreviations 
Fifty percent

50%  Fifty % 
Three hundred dollars  $300  Three hundred $ 
Six feet two inches  6’2”  Six’ two”
6 ft, two in 
Seventy pounds

70 lb  Seventy lb 
Twelve centimeters  12 cm  Twelve cm 