Which should I use "I understand" or "I understood"?

When I'm explained something from a teacher and the teacher asks me if I get what she's just explained, should I answer "I understand" or "I understood"?

In this case, we use "I see" with present tense and never say "I saw", but when the verb is "get", "I got it" sounds more natural for me (but I might be wrong).

So I'm wondering which tense is suitable for the verb "understand".

Thank you in advance :)

Question

Which should I use "I understand" or "I understood"?

When I'm explained something from a teacher and the teacher asks me if I get what she's just explained, should I answer "I understand" or "I understood"?

In this case, we use "I see" with present tense and never say "I saw", but when the verb is "get", "I got it" sounds more natural for me (but I might be wrong).

So I'm wondering which tense is suitable for the verb "understand".

Thank you in advance :)

Answer

"I understand" is more appropriate in this context.

This is a good question though, because both options make sense, but "I understand" is better.

Answer

I understand is best for your immediate answer.  Later on you can say 'I understood'
as in.. I understood you when you told me but now I have forgotten.

Answer

Well, understood is mostly used when someone has given you a command, order, request or a remark, so in this condition understood is used (as far as I have observed)

Answer

Thanks guys, I tend to use "I understood" but now "I understand" that I should use "I understand". Thank you so much ;)