Is it considered informal to omit "that" in "so ... that ..."? What would style guides say about the following?

John is so intelligent (that) he can learn any language in two months.

If this omission is used alongside a formal structure, would a stylistic mismatch arise?

The building is of such size and grandeur, (that) everyone feels great awe when they first see it.

Some style guides, notably The New Fowler's Modern English Usage and The Cambridge Guide to English Usage, both claim that should be retained in formal contexts involving compound conjunctions. Examples are offered below:

What would he do now (that) he had missed him in Toulouse?

The heat was up so high (that) almost everyone took off their coats.

We were so exhausted (that) we didn’t care.

They would be there provided (that) we did all the catering.

Do you agree with their judgments on these sentences? If so and if you still think that can be omitted in formal contexts involving compound conjunctions, could you provide some working guidelines about its omission?

I'd appreciate your help.

  • Comments are not for extended discussion; this conversation has been moved to chat. Any clarification of the question should be edited into the question instead of left in the comments.
    – ColleenV
    Aug 5, 2018 at 15:16

2 Answers 2


I would consider it informal or conversational.

John is so tall he can dunk the ball.

A mourning dove is so fast it can stay ahead of a kestrel.

The ride is so popular people are willing to wait three hours in line.

I think the majority of editors would insert that here:

Economic indicators have been so strong the Federal Reserve has made the decision to raise interest rates a quarter point.

P.S. of such {noun phrase} is more formal than so {adjective}. With of such {quality expressed by abstract noun or nouns} there can be a register shift and even a "clash" if the complement clause isn't introduced by that:

She is a woman of such sustained munificence the museum has been able to assemble a truly remarkable collection of Pre-Raphaelite paintings.

P.P.S. When the main clause becomes more ponderous or "weighty", additional syntactic undergirding is helpful, and so that tends to introduce the complement clause.

  • Is "be of abstract noun " a formal structure? E.g. He is of great intelligence ? Does it create a clash with so,,,(that)... with that omitted?
    – Apollyon
    Aug 5, 2018 at 13:35
  • 1
    @Apollyon: a man of great intelligence is not conversational. I'd need to see the actual sentence to judge whether there's a clash. The sentences here follow the pattern so {adjective} {finite clause}
    – TimR
    Aug 5, 2018 at 14:27
  • There is one such sentence in the OP: The building is of such size and grandeur, everyone feels great awe when they first see it.
    – Apollyon
    Aug 5, 2018 at 14:28
  • 1
    of such {noun phrase} is more formal than so {adjective} and IMO there can be a slight clash if that does not introduce the complement clause.
    – TimR
    Aug 5, 2018 at 14:34
  • 1
    Please see the P.S.
    – TimR
    Aug 5, 2018 at 14:43

Update: I had answered this question not knowing that the question had several assumptions behind it that were not made clear until comments were added to this answer.

  1. The use of that is more acceptable in formal writing than informal writing.

  2. Formality is better expressed with longer sentences.

I disagree with both of these assumptions. Formal writing can be precise and and follow a stricter set of adherence to grammar, while at the same time exercise style choices that aid comprehension. There is no context that can't benefit from the application of plain language.

If there is a situation where that hinders comprehension because it slows down the parsing of text, and where removing it doesn't damage the grammar, then it doesn't serve a purpose. The need for comprehension is even more important in formal text.

Omitting that is mostly one of style and, unless you're following a house style guide, it's quite subjective.

It really has little to do with it being informal or formal. Those who would argue against its overuse would want it removed from formal contexts too. In fact, people writing informally will seldom pay attention to the frequent use of that. It's actually more likely that those concerned with its overuse would removed it from formal writing than they would from informal writing.

I answered a similar question at English Language & Usage. Most of that answer is relevant, so I will quote it here:

Many people think that that should not be overused, and that sentences flow better without it.

From the blog post "Overuse of That" by Billie Jo Schinnerer:

My finding is many times it can be deleted without being missed and often increases the flow of the passage. For example in the sentence below:

She found that she did not like the soup.
She found she did not like the soup.

This is, of course, a subjective opinion. Some people may find the first sentence preferable, others the second. (I personally prefer the second sentence—without that.) . . .

But different sentences have different cadences, and sometimes it might sound more natural to include that in one and exclude it from another. The context in which a sentence exists (its surrounding text) also makes a difference.

There are some legitimate reasons why that should not be removed.

In the blog post "When to Delete 'That'," Neal Whitman (a guest blogger for Mignon Fogarty) gives the following example:

Sometimes, omitting a "that" after a non-bridge verb goes beyond being slightly awkward and can actually be confusing. Here’s an example from Bryan Garner’s Modern American Usage:

  • Son acknowledges being a member of a minority ... may have helped him turn his eyes abroad early.

The trouble here is that "acknowledge" can be a transitive verb. So when a noun phrase comes after it, such as "being a member of a minority," the reader might just take it as a direct object: “Son acknowledges being a member of a minority.” But whoops! The sentence keeps going, and the reader has to go back and reparse it. Garner calls this a miscue; sentences that produce miscues like this are called garden-path sentences.

He goes on to say the following:

Nouns that sound awkward if you delete a "that" include "fact." A phrase like "the fact Squiggly likes chocolate" is clear enough, but it’s really awkward-sounding.

He finally concludes:

If you’re a native English speaker, the main rule to follow here is to go by your ear. You probably know what sounds natural and what doesn’t, and all you need to do is give that native-speaker intuition more weight and authority than a rule stating that you should omit "that" whenever possible.

If you’re not a native speaker, I recommend keeping the "that" unless you’re dealing with a verb, noun, or adjective that you know will sound good without it. It’s safer to leave it in than to leave it out. As you write and read more, you’ll identify more of the words that allow you to omit "that."

  • What about sentences in my context?
    – Apollyon
    Aug 5, 2018 at 5:34
  • It's a fair answer, but it dodges the question of formality. Apollyon already understands "that" can sometimes be grammatically omitted. As you say, it's a question of personal style, which is why I recommend the question be edited to be more specific, or else be closed.
    – Andrew
    Aug 5, 2018 at 6:37
  • @Andrew Formality is mostly irrelevant to this issue. The prevalent style of removing extraneous instances of that applies as much to formal writing as it does to informal writing. In fact, a case could be made for the removal of that happening with more frequency in formal writing. (Because people tend to not "censor" themselves when writing informally.) If so, the situation is actually the reverse of what's claimed in the question. Aug 5, 2018 at 6:48
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    @Apollyon Both versions are fine grammatically with or without the use of that. (Without it, a comma should be used.) Aug 5, 2018 at 6:50
  • @JasonBassford Here's an excerpt from Robert Burchfield's The New Fowler's Modern English Usage: When the conjunction that is part of the correlative pairs so ... that, such ... that, now ... that (or so that, etc.), it is normally retained in formal writing but is sometimes omitted in informal contexts, e.g. What would he do now (that) he had missed him in Toulouse?; The heat was up so high (that) almost everyone took off their coats.
    – Apollyon
    Aug 5, 2018 at 9:14

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