Look Good in Print
02B: PUNCTUATION+
16. Know Your Numbers
Business relies on correctly expressing numbers. The following basic rules are consistent with the Chicago Manual of Style, but consult your particular company's style guide for any differences.
16.1 Generally, spell out single-digit numbers one through nine. Use numerals for double-digit numbers 10 - infinity.
YES: He realized he could eat 13 mandarin oranges and still consume fewer calories than he would by eating one glazed donut.
Be aware of the following exceptions to the general numbering rule.
- Spell out any number that begins a sentence
NO: 13 clients expect visits next week.
YES: Thirteen clients expect visits next week.
- Avoid starting sentences with large numbers.
NO: Four hundred and ninety five parking tickets were issued last month.
YES: Last month, the department issued 495 parking tickets.
- Write large numbers using a combination of decimals and verbal descriptors (million, billion, etc).
NO: At the end of 2016, Facebook had more than 1,790,000,000 monthly active users.
YES: At the end of 2016, Facebook had more than 1.79 billion monthly active users.
NO: The company had earnings of more than $4,200,000,000 over the last three years.
YES: The company had earnings of more than $4.2 billion over the last three years.
16.2 Percentages.
In written text, use the numeral and the percent symbol (e.g., 6%). However, check your company's style guide because some specify that all numbers be expressed as words (six percent); others use the
numeral with "percent" written out (6 percent). NEVER express percentages like this: six%.
In passages of text, round the percent to the nearest tenth: 11.57% becomes 11.6%.
16.3 Dates.
Generally use the cardinal (1, 2, 3) number for the date. The ordinal numbers (1st, 2nd, 3rd) are allowable only if the date precedes the month. Although we often interchange the cardinal and the ordinal forms when we talk, follow this rule in writing.
OK: The store opened on Saturday, the 12th of July, 2016.
BETTER: The store opened on Saturday, July 12, 2016.
PREFERRED FOR NON-U.S. AUDIENCES: The store opened on Saturday, 12 July 2016.
NO: The store opened on Saturday, July 12th, 2006.
16.4 Monetary amounts.
Use the currency sign with no decimals for whole numbers ($20). For fractions of dollars (or other currency), use the decimal expression ($20.56).
The basic principle of parallelism suggests that you NOT mix the two in a single sentence.
NO: The movie ticket cost $7.75, but I had only $5.
Instead, make the expressions consistent by using the decimal expression with both:
YES: The movie ticket cost $7.75, but I had only $5.00.
16.5 Time.
For a round hour without minutes, use the whole number, but when another time expression in the sentence includes the minutes, make both consistent. (This is yet another application of parallelism). Use lowercase a.m. and p.m. to indicate morning or afternoon/evening as needed. In business writing, never use the word "o'clock".
YES: Jason wanted to start at 11 a.m.
YES: Jason wanted to start at 11:00 a.m., but we didn't start until 12:30 p.m.
16.6 Fractions.
When expressing fractions, express standalone fractions as words and hyphenate them:
NO: Only ¾ of the students passed the exam.
YES: Only three-fourths of the students passed the exam.
However, use decimals wherever possible.
NO: After going west for five-and-a-quarter miles, travel three-and-a-half miles north on the main road.
YES: After going west for 5.25 miles, travel 3.5 miles north on the main road.
16.7 Page numbers.
When referring to a page or chapter number, always use numerals:
NO: You'll find the quote on page five of chapter eleven.
YES: You'll find the quote on page 5 of chapter 11.
16.8 Format numbers consistently within sentences.
Despite all of the above-mentioned rules, keep your formatting consistent within a sentence.
NO: Lila found 58 markers, 12 notebooks, and seven file folders in the storage room.
YES: Lila found 58 markers, 12 notebooks, and 7 file folders in the storage room.