What is the correct way to write a range of dollar figures?

Question

What is the best way to express the range from $4.5 billion to $5.2 billion?

Is the following correct?

... between $4.5 and $5.2 billion ...

Answer 1

According to this guide on using numbers in writing, when writing numbers:

The simplest way to express large numbers is best. Round numbers are usually spelled out. Be careful to be consistent within a sentence.

It goes on to give the following examples which are all considered correct:

• You can earn from one million to five million dollars.

• You can earn from five hundred to five million dollars.

• You can earn from $5 hundred to $5 million.

Since the key is to be consistent and keep it simple, I would suggest writing your range of numbers like this:

between $4.5 billion and $5.2 billion

There is an example from the Wall Street Journal that uses this style, citing:

between $50 million and $57 million per season

You can also omit the first "billion" since your decimal of 4.5 probably won't be confused with $4.50. There is an example in writing here which refers to the range "between $85 and $190 million", so you can expect that people would understand the omitted "million" or "billion".

Though there are examples for both, it may be best to keep both "billions" in formal writing, so as to decrease any possible ambiguity.

Answer 2

According to this site, use figures only when it takes more than three words to spell out the number:

"Spell out numbers of one or two words or those that begin a sentence. Use figures for numbers that require more than two words to spell out. [Examples:] It's been eight years since I visited Peru. I counted 176 DVDs on the shelf.

If a sentence begins with a number, spell out the number or rewrite the sentence. [Example:] One hundred fifty children in our program need expensive dental treatment.

Exceptions: In technical and some business writing, figures are preferred even when spellings would be brief, but usage varies. When in doubt, consult the style guide of the organization for which you are writing. When several numbers appear in the same passage, many writers choose consistence rather than strict adherence to the rule. When one number immediately follows another, spell out one and use figures for the other: three 100-meter events, 25 four-poster beds.

Thus, it would be written:

between four million and five million.