“I know.” vs “Ik weet het.”

When you learn Dutch, it’s tempting to translate directly from English. But some verbs behave differently — and weten (“to know”) is a good example.

In English, you can simply say:
“Yes, I know.”

In Dutch, this doesn’t work.
You cannot say: “Ja, ik weet.”
Because weten always needs a direct object — something you know. That can be a word or a whole clause.
Ja, ik weet het.
Ja, dat weet ik.
Ja, ik weet dat…

You can also say: “Nee, ik weet niet.”
In that case, you don’t need a direct object. Because the information you want to deliver here is already complete.