[tgodbold]

When writing a business letter, what is the rule for spelling out numbers and using just the numeral?

[Gregisteredtrademark]

According to the APA Publication Manual, you should use words to express any number that begins a sentence, title, or text heading. (Whenever possible, reword the sentence to avoid beginning with a number.)

For example:

Ten participants answered the questionnaire.

Forty-eight percent of the sample showed an increase; 2% showed no change.

Four patients improved, and 4 patients did not improve.

[dawgsnkats]

Remember, in business everything you write can be considered a contract. It is best practice to use numbers and words when describing values. This leaves nothing to error when engaged in price or performance. The APA is a good reference for publishing.

[LucyBennett]

For a little more detail, the AP Style book is helpful. Here's my summary of AP's rules:

General: Spell out whole numbers one through eleven.

Main Exception: Numbers at the beginning of a sentence are always spelled out. Sometimes it's easier to just rewrite the sentence. One exception to this rule is a calendar year. Example: 2009 was a good year.

The following are ALWAYS figures:

• Ages
• Measurements and dimensions
• Monetary units
• Million, billion
• Percentages

[dontknownuthin]

Another rule I follow is that if a number is in the body of the letter (not the start of a sentence) I write out single digit numbers, and use numerals for larger numbers. It's less awkward than, for example, writing out "Two hundred and seventy two thousand four hundred dollars" to write "$273,400." Our brains do not process large numbers that are written out very well.

And another option is to do both:

"As we discussed, the overall cost for completing the new hospital wing will be One million, two hundred thousand dollars ($1.2 million)."