How high should your desk be?

Most office desks are approximately 90 cms high which is a good height for most.

The key to good desk height is that you need your forearms to be at a slight angle with your hands lower than your elbows when using your keyboard and mouse.

office ergonomics

Using a kitchen table can be a really bad idea because it can either be too high or the bar that is often beneath the tabletop will not allow your seat to be raised high tables cause RSI