Numbers in Writing

When the piece of writing contains few numerals, write out numbers that can be expressed in one or two words, as shown in these examples:

zero
fourteen
twenty-two
six hundred

When the piece of writing contains many numbers, write out numbers one to nine. Use numerals for numbers above nine. Combine numerals and words for large numbers.

one
three
nine
11
123
29,267
100 million
36 billion
12 trillion

Write out numbers at the beginning of a sentence. Do not begin a sentence with numerals.

Incorrect: 22 people were standing in line.
Correct: Twenty-two people were standing in line.

Use numerals with A.M. or P.M. Use words with o’clock.

2:30 p.m.
three o’clock

Finally, use numerals for percentages, measurements, scores, or statistics, as in these examples:

35 mph
1.2 liters
73%
5’10”

Which sentence is correct? The airline claims that its flights are on time ninety-five % of the time, but our flight, which arrived at 6 o’clock, was 2 hours late. Of the 395 people who attended the conference in San Francisco, seventeen of them were from California, five were from Hawaii, and the remaining 373 people were from the other 48 states.