Cool MateI don't know vs I'm not really sure yet
When to use each in English, with meaning, register, and examples.
I don't know
Top 1,000 (very common)
I'm not really sure yet
Top 1,000 (very common)
| I don't know | I'm not really sure yet | |
|---|---|---|
| Pronunciation | 🇬🇧 //aɪ dəʊnt nəʊ//🇺🇸 //aɪ doʊnt noʊ// | 🇬🇧 //aɪm nɒt ˈrɪəli ʃʊə jɛt//🇺🇸 //aɪm nɑt ˈrɪəli ʃʊr jɛt// |
| Meaning | I am not sure. | I don't know for certain right now. |
| Example | What time is the meeting? I don't know. | I'm not really sure yet what time the meeting starts. |
| Register | Neutral | Neutral |
| How common | Top 1,000 (very common) | Top 1,000 (very common) |
| Collocations | I don't know what, I don't know why, I don't know how | I'm not sure yet about that, I'm not really sure yet how to proceed, I'm not sure yet what to think |
| Antonyms | I know, I am sure, I understand | - |
| Common mistakes | Using it too formally in professional settings., Saying 'I not know' instead of 'I don't know'., Confusing it with 'I don't know how'. | Using it too formally in business meetings., Confusing it with 'I'm sure' which means the opposite., Omitting 'yet' and saying 'I'm not really sure'. |
| Usage notes | Use in conversations when unsure about an answer. Avoid in formal situations where providing a response is expected. | Use this phrase in casual conversations when expressing uncertainty. Avoid in formal or academic contexts. |
See it in real clips
Frequently asked questions: I don't know vs I'm not really sure yet
What's the difference between I don't know and I'm not really sure yet?
I don't know: I am not sure. I'm not really sure yet: I don't know for certain right now.
Can you show an example of each?
I don't know: What time is the meeting? I don't know. I'm not really sure yet: I'm not really sure yet what time the meeting starts.
Can I use I don't know and I'm not really sure yet interchangeably?
Not always. I don't know and I'm not really sure yet are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.