I have difficulty understanding comma usages in the following sentences:

  1. Mr Hirai had already announced that Sony's TV production goal would be halved, from 40m units to 20m. (The Economist)

Why is the comma placed after "halved?" In the following sentence, which is also from a British newspaper, no comma is used:

As reported, the charge for crossing the bridge will be halved from £3 to £1.50 for cars.


-2. And while unemployment is a modest 6.4% and declining, inflation has picked up sharply, to an estimated 6.5%, more than a point higher than last year. (The Wall Street Journal)

Is the comma after "sharply" necessary? What the difference in nuance with and without the comma?

-3. The government of Prime Minister Naoto Kan has proposed doubling, to 20%, the tax on capital gains and dividends. (The Wall Street Journal)

Why is "to 20%" set off by the commas?

Could anybody shed light on these comma usages?

4 Answers 4


All the commas you noted are a stylistic preference. In my own writing, I'd probably omit them.

  • +1: In general I'd like to think I'd omit all those commas too, but if I'm honest I had to make a real effort to stop myself putting one after the word "general" there. Google sends me here if I search for "society for the preservation of t" (which it knows to autocomplete with the apostrophe), but personally I think the numbers are getting out of control, and we should be more focussed on "culling the apostrophe" (sadly, it's "No results found" for that one! :) Apr 15, 2012 at 21:14
  • The commas alter the emphasis, and so the meaning the reader will pick up; in that sense, they're not optional. Apr 16, 2012 at 20:28
  • +1 The sentences are grammatically correct, and I thought the commas felt right there, where zpletan would omit them. Commas are often required, but are often personal preference.
    – Carl Smith
    Oct 13, 2013 at 16:22
  • @zpletan I presume your own comma after 'writing' was written with irony...
    – toandfro
    Mar 11, 2014 at 6:47

In all the cases above, the commas set off supplementary information. It can be added, almost as an afterthought, or removed. In the first two cases, the comma is, I would argue, optional. You can certainly find many analogous cases in edited, published material where it is omitted. In the last cases, the supplement, coming as it does between the verb and the object, presents a stronger case for commas. Commas, though, are often as much a matter of style as of rules. As Adam Freedman has said, "In the 18th century, punctuation marks were as common as medicinal leeches and just about as scientific." To think that we've now made them entirely scientific would be naive.

  • I disagree that in (3) the commas are required, because the parenthetical text comes between the verb and the object. I know there are lots of irrelevant matches in Google Books for "doubling to * the", but there are an awful lot of perfectly valid constructions there that don't enclose to [some doubled value] within commas. The commas are just an aid to legibility - but they aren't always needed, or even desirable. Apr 15, 2012 at 21:06
  • Yes, when it comes to commas, "required" is likely too strong a word. Apr 15, 2012 at 22:15
  • 2
    @FumbleFingers: Tell me what you think of this: If a car dealer is offering to double my down payment up to 20% of the sales price, I'd write that as "We'll double your down payment [up] to 20% (without the commas). So it constrains the doubling. With the commas, the 'to 20%' tells us that the doubled amount is equal to 20% (my original must have been 10%). So the commas explain the doubling.
    – Jim
    Apr 15, 2012 at 22:23
  • @Jim: I don't understand the context at all. In what sense would a car dealer be "offering" if he's demanding a higher down payment? Sure, he could say, for example, "If you can find this car cheaper elsewhere, we'll reduce our price by double the difference (up to $1000)". Apr 15, 2012 at 22:36
  • 2
    ...oic - I think perhaps you're using "double" there where in Br. Eng. we normally say "match" (the dealer will effectively discount your price by the amount of your down payment). I don't think commas (or brackets) can be relied on to remove potential ambiguity on whether you end up with 10% or 20% off the final price paid. I would question the guy carefully, in the expectation that he was trying to cheat me anyway (he is a car dealer, after all!) Apr 15, 2012 at 22:40

In the last example, setting off by commas makes the phrase to 20% parenthetical: the sentence is complete without it, the parenthetical part adding some extra detail.

Also, the use of the comma shifts the focus. That Sony's TV production is 40m and will reduce to 20m is the main point here. Note the context: The Economist, hence figures matter.

Charges for crossing the bridge have been halved. That's the real news. The charges themselves are a minor detail, just in case you didn't already know. Hence no comma needed.

  • It seems to me that the emphasis is exactly the other way; without the comma the reader's attention would naturally fall on the last part of the sentence (bridge tolls are now £1.50). If the writer wishes to emphasise that production has halved, he inserts a comma to focus attention on the word before it. Apr 16, 2012 at 12:55

I think the commas are unnecessary in all cases. As has been pointed out, comma use is often a matter of preference. It is also useful to indicate to someone reading out loud when to pause. Most of the sentences also contain otiose statements. For example, in the phrase "halved from £3 to £1.50 for cars. why is it necessary to write "to £1.50? What else would you get if you halved £3.00?

  • 1
    Probably quoting a tabloid. The people that read those things would really appreciate the author having done the math for them. In the original, it probably came with a pie chart.
    – Carl Smith
    Oct 13, 2013 at 16:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.