Numbers
Numerals Versus Words
Spell out numbers below 10. Use numerals for 10 and above.
You may use a numeral in a headline if it makes sense or improves the effectiveness of the headline.
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Use numerals if you’re making a comparison.
There were 4 members on the red team and only 3 on the blue.
However, use good judgment. Sometimes you will be comparing two things that require numerals, but you’ll need to spell out an additional number that is not part of the comparison.
During the entire three-day event, there were 250 books and 125 magazines donated.
If a number is in the millions or greater, use the numeral first and then write out the word million, billion, trillion, etc.
If a number begins a sentence, spell it out.
Punctuation and Formatting
When writing out a numeric occurrence, don’t use superscripts; just add “th.”
It was their 50th anniversary.
When writing out page numbers, addresses, or years, use a comma for four or more digits (such as 4,000 BC).
You should hyphenate when the number is describing something else.
They recently crossed the 2-million customer mark.
You may abbreviate million as mil, billion as bil, and thousand as K, but do so consistently.
Ages
For living things, use numerals when stating an age. For objects (a company, building, or city), spell the number out when it is less than 10.
Example
Her 5-year-old daughter is well-behaved.
The building is four years old.
Fractions and Decimals
To write out a fraction, use a hyphen to separate the numerator and denominator.
Three-quarters of the company is based in Minneapolis.
When possible, use numerals for mixed numbers (such as 10 3/4), but if they must be spelled out, hyphenate the fraction like so: ten and three-quarters. Do not use special characters such as ¾ that may not translate to code properly.
When possible, use decimals to indicate a value instead of fractions, but use the smallest number of decimal points possible (5.300 can be written simply as 5.3).
For amounts less than one, include a leading zero like so: 0.75.
Measurements
Always use numerals to describe dimensions. Use an "x" whenever possible as a substitute for the word "by."
He moved into a 10' x 10' apartment on the Lower East Side.
Hyphenate numerals and units of measure.
The truck couldn’t clear the 12-foot overpass.
When formatting a combination of units, like someone’s height, use the following symbols:
- ‘ to indicate feet
- “ to indicate inches
The basketball team had a 6’10” center.
If you must write a measurement like this out, format it as so: The basketball team had a 6-foot-10-inch center.
When space demands, you may use customary abbreviations such as “in” for inches, “ft” for feet, and “yd” for yards.
Do not repeat units of measure for each number.
The company rented a 300 x 500 ft office space.
Money
Use numerals and the $ symbol to indicate currency-related figures.
He bought a $20 Metrocard.
It’s not necessary to add the .00 at the end of every price, but it’s appropriate if you’re comparing prices.
Starbucks wants to charge me $4.00, but I can get a coffee on the corner for $1.75.
Use a comma when a dollar amount is four or more digits.
The ring cost him $5,000.
Ranges
Use numerals to indicate numbers in ranges, and separate ranges of numbers with a hyphen with one space on either side.
The dish serves 8 -10 guests.
For an open range of numbers, use an em dash without a space.
Barack Obama (1961—) is the 44th president of the U.S.
Percentages
Use numerals with the percent sign (%) instead of writing the word “percent.” The percent sign is easy to spot and clear in meaning.
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