They aren't too loud. Almost like a Mac keyboard but not. Somewhere between a Mac and normal desktop keyboard. I was typing while skyping and my girlfriend said she could hear me type. Then again, I'm a little more aggressive than I need to be. So no, it does not make a loud clacking noise that some traditional keyboards do.
It does not make a loud clacking noise but it does make noise. The keys are softer than the traditional desktop keyboards I have used. When I was typing, my friend did hear the keys over the phone and he said it's audible like a regular keyboard.
oops. Wen, I think I hit no for your review being helpful. Should have hit yes. They are better than standard keyboards but still kinda noisy. They are smoother which helps with that some. Hope this and the other answers helped you.
two notes. The wireless feature goes off and on on occasion. So the Keyboard and/or mouse won't work for 30% of the time :( approx 70% of the time it works great and the other 30% doesn't work good or work at all for that matter. The Keyboard is very quiet.