I learned English long time ago. The native speaker teacher told me that we always use comma after the word then. However, one proofreader told me that I must not write a comma after then. I am really confuse. Could some one please explain to me when it is correct to use comma with then?

For example,

Then, the next step is estimating the model parameters.

Set x as a first point, then, find the point y given x.

  • Could you add a few examples of either case?
    – CinCout
    Feb 28, 2019 at 5:42

2 Answers 2


There are some circumstances that a comma should be used after then:

"It is good, then, that you wish to learn more."

But your examples aren't such circumstances. When using then to indicate a sequence of events, either in reporting events or giving instructions, it should not normally have a comma (though there are always exceptions, like there being a parenthetical clause immediately after it). When used in a similar sense to therefore, it may or may not want a comma after it - to the same standards as if you were using the word therefore.


Then can be used as an adverb, conjunction, noun, and an adjective. There is no definitive answer to your question because

  • as it frequently introduces a dependent phrase, however, a comma would be placed at the end of the independent phrase or clause which precedes it.
  • The use of a comma is more art than science. What’s ‘correct’ varies depending on the sense and composition of a sentence. In general, you should probably place a comma at every point where you would pause if you were reading the words you’re writing out loud. It’s virtually mandatory to use them to separate words or phrases in a list (They were red, white, smooth in texture, and triangular in shape). They’re also very helpful in setting-off clauses that:
  • describe separate actions (went to the office; left for the airport)
  • communicate descriptive information that’s important but without which the rest of the sentence would still make sense (around noon). Some people use commas a lot more than others. As a ‘rule of thumb’: if your sentence needs too many commas, it needs to be re-written and you probably have clauses in it that should be sentences on their own. Conjunctive adverbs are followed by a comma. Examples:
  • I ate, then I started home.( adverb )
  • Read the instructions well , then start answering. (conjunction )

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