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Comma before or after “so”: The Definitive Guide

Comma before or after “so”: The Definitive Guide

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One of the many troubles encountered in writing is with multifaceted words and punctuation marks.

Words wearing multiple faces are tricky because we could get tangled up in which denotation or connotation should be applied in what sense.

Punctuations, especially commas, are but sneaky too since they have more grammatical and stylistic rules to follow.

Well, it doesn’t have to be that bad, does it?

Let’s now take a closer look at comma-decisions before and after a word as flexible as bamboo — so.


Do we need a comma before or after “so”?

In most cases, except particularly when acting as a coordinating conjunction or parenthetical element, commas aren’t necessary with so.

Comma placement before so is applied when it is used as a parenthetical component for stylistic reasons.

Meanwhile, a comma after so is essentially inserted when it is used as a coordinating conjunction combining two independent clauses denoting a cause-and-effect relationship.

Moreover, a comma is also necessary after so when it is followed by a parenthetical expression.

Consequently, no commas are needed when it is used in all its other adverbial and subordinating conjunction senses.

Comma Usage With So


Comma before “so” in more detail

All of us must have had doubtful moments whether or not to hook a comma before so in sentences.

Despite that, this decision mainly lies in two writing circumstances: (1) when using it as a coordinating conjunction and (2) when inserting it as a parenthetical element.

Let’s look at each function in detail.


So as a coordinating conjunction

Recalling one of the most fundamental ways to classify conjunctions, so is one of those with a coordinating function.

Coordinating conjunctions bind words, phrases, and clauses that are of equal importance in a sentence.

You may also remember them mnemonically as FANBOYS (for, and, nor, but, or, yet, and so).

So, in particular, means “for the reason mentioned” which is used to connect the consequence or effect of another implied action or circumstance.

Syntactically, the conjunction so is used to conjoin two clauses with a complete thought (independent clauses) and with equal weight.

A comma is essentially put before so in this case.

He has been feeling ill for several days now, so he booked a medical check-up.
His two front teeth were about ten miles apart before, so we nicknamed him Goofy.

Comma Rules Cheat Sheet


So as a parenthetical element

The other case that necessitates a comma insertion before so is when it is used as a parenthetical expression.

Parentheticals are thoughts or information inserted halfway through the sentence or at the end as a means to provide extra layers of details that are grammatically dispensable.

A comma insertion is also necessary before the first word of every parenthetical expression, and so can be used in any sense or meaning.

He’s unable to carry the four puppies all together, so he placed two down, and headed towards the car.
The attic’s ceiling, so low that one has to forcefully duck, conceals a secret room.


Comma after “so” in more detail

Grammar prescriptivists traditionally prohibit the use of so, but, or and at the sentence-initial position.

However, as linguistic norms have changed and evolved, it has also prompted the acceptance of such cohesive devices as sentence starters particularly in spoken language and informal writing.


So as a conjunctive adverb

Conjunctions that also carry adverbial function are known as conjunctive adverbs or adverbial connectors.

Although the use of so in the sentence-initial position is not advisable in formal writing because of the presence of other better cohesive devices to use, language evolution has allowed it to be utilized as a conjunctive adverb in the modern age.

On that note, as conjunctive adverbs normally require a succeeding comma placement, this rule should also similarly apply to so, especially when transitioning to substantially noteworthy information.

You’ve already been dating him for five years now and you seem to have an utterly stable relationship. So, I believe someone’s getting hitched soon.


So preceding a parenthetical expression

This next rule more likely has grammatical grounds, and thus strictly necessitating comma use right after so even if it is sentence-initially placed.

As mentioned some paragraphs ago, parenthetical elements have to be encapsulated from the rest of the sentence with commas to set its distinction apart.

Therefore, when so is followed by a parenthetical expression, a comma is always necessary after it.

So, if you would allow, I’d like to move in with your daughter two months from now.


When is a comma not necessary with so?

As an adverb, so has several usages, and the ones listed below do not require commas either or both before or after it.


So, the adverb of degree

One of the most basic lexical meanings of so is the one that denotes the same as “very” or “to a high extent”.

When used in this sense, it can either be called an adverb of degree or intensifier whose job is to add another layer of emotional implication of what is being modified.

Martha has never been so in love until she met Dylan.


So as similar to also

When adverbs serve their purpose to add or supplement relevant details of another idea that has been mentioned, we refer to them as additive adverbs.

So may also be an indirect substitute to also as an additive adverb, and when used like this, comma placement is unnecessary.

She has fallen out of love, and so did he.


So as a subordinating conjunction

Although it was mentioned earlier that so mainly functions as a coordinating conjunction, it can, however, also function as a subordinating conjunction tying up an independent and a dependent clause together.

Bear in mind that a subordinating clause is something that cannot stand alone, therefore lacking either a subject or a verb.

In tying a dependent clause with so, a comma is not used before or after it.

Dad has installed surveillance cameras so as to ensure our safety.



Although comma decisions with multi-meaning words drag both native and non-native writers alike, it is still better to practice proper usage.

As language evolves, lexical and grammatical changes may also be observed, thereby essentializing adaptive behaviors in the process.

This means that although some changes may seem unconventional, albeit tasking and awkward, we still need to adjust and cope with the said variations.

Thus, language is a living organism that thrives with human civilization.