When writing out large numbers in words, should commas be placed at thousand separators?

Solution 1:

It's a style guide thing in my op, but if you're writing out numerals that large in a block paragraph, I would recommend using the commas for readability purposes - a string of text numerals is hard to parse - and it also sounds better (I'm relatively sure most people insert pauses between logical digit groupings).

I'll admit to influence being ex APS (Australian Public Service), but we do tend to do a lot of writing and our style guidelines have been hammered out specifically with a view to making sure that the relevant information gets to the eyes of the target reader, in a form with the lowest chance of it being mangled.

Paraphrasing our guide (specific reference below) and personal experience, three other suggestions:

• If you can, place the numeric form after the string. The numbers are much easier to scan for in text, and give a quicker indication of 'sizeness'.

  five million, two hundred and fifty thousand, four hundred and twenty-two (5 250 422)

• I'd also suggest retaining the and within digit blocks. In my op, it's more natural but also binds the numerals together indicating who belongs to which group.

  four hundred and twenty-two

  not

  four hundred twenty two

• Finally, hyphenate between the tens and ones of a group of digits, again for readability.

  two million, fifty-four thousand, nine hundred and ninety-nine.

  not

  two million, fifty four thousand, nine hundred and ninety nine.

I thought it was a bit silly when first having to internalise the style guide, but after a while it starts to make sense, for example in a straight side-by-side:

Five million six hundred twenty nine thousand two hundred ninety six

Five million, six hundred and twenty-nine thousand, two hundred and ninety-six (5 629 296)

Of course, your internal guides (or the prevailing style in your area, I have a funny feeling AmE might drop the internal ands for instance) will have their own suggestions, and consistency is king with something like this.

Source: Old habits from a stint in the Australian Public Service as a policy officer, and the Style Manual (6th ed), pg 176. (ISBN 978-0-7016-3648-7)

Solution 2:

I think this is a question of readability. From my own experience the use of commas and the breaking up of the numbers into groups of three is optional, however in some ways has become a convention. When converting this into text, the same would apply. In most cases, spelling the number with the same commas as used when in numerical form facilitates readability. The only case where this may become confusing is if you were listing large numbers in a sentence, in which case leave them out.

Solution 3:

As a supplement to BrainFRZ's very useful answer discussing the style recommendations of APA, MLA, and Chicago, I note comparable advice from Words into Type and the AP Stylebook. From Words into Type, third edition (1974):

When isolated numbers (that is, numbers that appear only rarely in a manuscript) are spelled out, it is unnecessary to use and following the word hundred or thousand (although in formal literary and legal contexts and may be used).

two hundred fifty-six

seven hundred forty

six thousand nineteen

forty-six thousand two hundred seventy-two

The absence of a comma after "forty-six thousand" in the fourth example is especially noteworthy.

From The Associated Press Stylebook and Briefing on Media Law (2002):

LARGE NUMBERS: When large numbers must be spelled out, use a hyphen to connect a word ending in y to another word; do not use commas between other separate words that are part of one number: twenty; thirty; twenty-one; thirty-one; one hundred forty-three; one thousand one hundred fifty-five; one million two hundred seventy-six thousand five hundred eighty-seven.

It thus appears that Chicago, AP, and Words into Type—which are probably the three most influential style guides in mainstream, nonspecialized U.S. publishing—align on the view that commas should not appear within spelled-out long numbers.

Unfortunately, the Oxford style guide (my primary source of information on style preferences in British English) doesn't address this question, perhaps because its authors imagine that writers and editors can work around the problem by recasting sentences so that the number doesn't appear at the beginning, and therefore can be handled in numerals rather than being spelled out. But since the OP has tagged the question here as "american-english," I assume that U.S. style conventions are most relevant.

Solution 4:

Use of the word 'and' in written numbers should only be included when separating the whole and fractional part of the number. Example 300.075 versus 0.375. and 375. If we name 375 accepting and we get three hundred and seventy-five. Naming fractions we name the numerator as a cardinal number and the denominator as an ordinal number so we would get three hundred and seventy five thousandths using this convention with 'and' included in whole numbers. This results in the ambiguous case(albeit rare) where the and could be just for 'style' or it would mean separating the fractional part from the whole number part - that is 300.075 versus 0.375. To correctly name 0.375 write three hundred seventy-five-thousandths and to name 300.075 write three hundred and seventy-five-thousandths.

interpreting two hundred and ninety-six as 200.96 is incorrect because the name does not tell us hundredths (as is the case in 200.96. It could be 200.096 (thousandths) or 200.00096(hundred thousandths. The word 'and' in math does mean 'add' so two hundredth and fifty thousandth could be interpreted as 50,000 + 200 but if we are randomly inserting ands it could well mean 250,000 too. This isn't such a big deal though as the convention is to write numbers (in prose or with digits) in descending order. Omit 'and' unless you are dividing a whole number from a fractional part two hundred and three-eights means 200 +3/8 not 203/8.