not sure whether

USAGE SUMMARY

'not sure whether' is correct and usable in written English.
You can use it when expressing uncertainty about something. For example: I'm not sure whether I will have enough time to finish this project before the deadline.

✓ Grammatically correct

News & Media

Academia

Wiki

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

So, I'm not sure whether it's bad.

Yale University

I'm not sure whether he did either.

The Guardian - Film

"I'm not sure whether to believe him".

The Guardian - Books

I'm now not sure whether she had.

The Guardian - Lifestyle

I'm not sure whether that will happen.

The New York Times

"I am not sure whether they'd overturn.

The Washington Post

Not sure whether red lipstick's your thing?

The Washington Post

Metaphysically, I'm not sure whether that's a possibility or not.

Yale University

I'm not sure whether Samuelson had read Allais.

Yale University

I am not sure whether that is common or not.

Massachusetts Institute of Technology

Furthermore, they were not sure whether the rumor was true.

The New York Times

Expert writing Tips

Best practice

Use "not sure whether" to introduce a question or dilemma, prompting further investigation or discussion. For example, "I'm not sure whether this is the best approach; let's explore other options."

Common error

Avoid using "not sure whether or not", as the "or not" is often redundant. "Not sure whether" already implies uncertainty about both possibilities. For example, prefer "I'm not sure whether it will rain" over "I'm not sure whether it will rain or not".

Linguistic Context

The phrase "not sure whether" functions as a connector, introducing uncertainty or doubt regarding a specific condition or possibility. It's commonly used to present alternatives or express a lack of definitive knowledge. Ludwig AI confirms its correct and usable status in written English.

Expression frequency: Very common

Frequent in

News & Media

55%

Academia

20%

Wiki

10%

Less common in

Science

5%

Formal & Business

5%

Reference

5%

Ludwig's WRAP-UP

In summary, "not sure whether" is a highly versatile and commonly used phrase for expressing uncertainty or doubt. Ludwig AI confirms its grammatical correctness and broad applicability, as it appears frequently across diverse sources, particularly in news, academic, and wiki content. When writing, it's important to avoid redundancy by omitting the "or not" unless absolutely necessary for clarity. Remember to consider alternatives such as "unsure if" or "doubtful if" to add variety to your writing. It is important to emphasize that the expression is suitable for neutral contexts, with no major constraints in terms of formality. The usage guidelines provided should prevent common mistakes and make you a more confident and skilled writer.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

unsure if

Replaces "whether" with "if", creating a slightly more informal tone.

not certain if

Substitutes "sure" with "certain", adding a touch of formality while maintaining the core meaning.

doubtful if

Uses "doubtful" to emphasize the lack of certainty, shifting the focus slightly towards skepticism.

questioning whether

Replaces "not sure" with "questioning", highlighting the act of considering the possibilities.

wondering whether

Implies a sense of curiosity or contemplation regarding the situation.

not convinced that

Shifts the focus to a lack of belief or persuasion, rather than simple uncertainty.

have my doubts about

Expresses a degree of skepticism or reservation about something.

it's uncertain if

Introduces an impersonal construction, distancing the speaker from the uncertainty.

it remains to be seen whether

Indicates that the outcome is yet to be determined, emphasizing the passage of time.

I'm of two minds about

Suggests conflicting opinions or feelings, rather than a simple lack of certainty.

FAQs

How do I use "not sure whether" in a sentence?

Use "not sure whether" to express uncertainty about two or more possibilities. For example, "I'm "not sure whether" I should accept the job offer or continue my job search."

What can I say instead of "not sure whether"?

You can use alternatives like "unsure if", "not certain if", or "doubtful if" to express a similar meaning.

Is it correct to say "not sure whether or not"?

While grammatically permissible, "not sure whether or not" is often considered redundant. The "or not" is usually implied in "not sure whether", making the phrase more concise without it. Stick with ""not sure whether"" for cleaner writing.

What's the difference between "not sure whether" and "not sure if"?

Both phrases express uncertainty, but "not sure whether" is generally considered more formal than "not sure if". In most contexts, they are interchangeable, but ""not sure whether"" might be preferred in formal writing.