I know so

USAGE SUMMARY

"I know so" is correct and usable in written English.
You can use this phrase to agree with a statement someone else just made or to express certainty about a particular fact. For example, if someone said, "It's going to rain tomorrow," you could reply, "I know so."

✓ Grammatically correct

News & Media

Human-verified examples from authoritative sources

Exact Expressions

59 human-written examples

I know so, and so do you.

The New Yorker

"I know so," he answered.

The New York Times

I know, so don't even bother saying you weren't".

The New Yorker

I know so many families who share this situation.

The New York Times

"I know so many people who can't.

The New York Times

Why? "Because," he said, "I know so".

The New York Times

I know so many wonderful people here!

The Guardian - Sport

I know so many others who'd be willing to help.

The Guardian

JED: I know, so I'm shading in the extra box.

The Guardian

"I felt so then; I know so now," he said.

The New York Times

Because I know so much about it now".

The New York Times

Expert writing Tips

Best practice

Use "I know so" to express strong agreement or certainty, especially in informal conversations. Be mindful of the context to ensure it doesn't come across as arrogant or dismissive.

Common error

Avoid using "I know so" in formal writing or professional settings, as it can sound too casual. Opt for more formal alternatives like "I am certain of that" or "I understand that" for a more appropriate tone.

Linguistic Context

The primary grammatical function of "I know so" is as an affirmative response expressing agreement or certainty. Ludwig AI confirms this usage, showcasing instances where the phrase is used to concur with a previous statement or to emphasize one's own conviction.

Expression frequency: Very common

Frequent in

News & Media

70%

Formal & Business

15%

Science

15%

Less common in

Wiki

0%

Encyclopedias

0%

Reference

0%

Ludwig's WRAP-UP

In summary, "I know so" is a common phrase used to express agreement or certainty, as confirmed by Ludwig AI. While grammatically correct, its usage is generally limited to neutral to informal contexts, making it unsuitable for formal writing or professional settings. The phrase is frequently found in news and media, as demonstrated by the examples from sources like The New York Times and The Guardian. When in doubt, consider more formal alternatives like ""I am certain of that"" or ""I understand that"" for a more appropriate tone.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

I'm certain of that

Expresses assurance about the fact.

I understand that

Focuses on the understanding of the matter.

I know that

Focuses on knowing a specific piece of information, adding more clarity.

I see that

Implies understanding or agreement, often in response to a statement.

I am aware of that

Highlights the awareness of the statement or situation.

I'm well aware

Emphasizes the depth of knowledge or understanding.

I'm conscious of that

Highlights the awareness of something in a specific way.

I get it

An informal way of saying "I understand".

That's right

Confirms the validity of the previous statement.

Indeed, I do

Affirms the truth, usually with more enthusiasm.

FAQs

How can I use "I know so" in a sentence?

You can use "I know so" to express agreement or certainty. For example, if someone says, "The traffic will be terrible tomorrow", you could reply, "I know so".

What's a more formal way to say "I know so"?

Alternatives include "I am certain of that", "I understand that", or "I am aware of that", depending on the context.

When is it appropriate to use "I know so"?

"I know so" is best used in informal settings or casual conversations where a less formal tone is acceptable. In formal settings, opt for a more professional expression.

Are there situations where using "I know so" might be inappropriate?

Yes, it can sound arrogant or dismissive in formal contexts or when speaking with someone who holds a position of authority. Consider using "I believe so" or "I think so" if you wish to sound less affirmative.