To get your bedside table height just right, aim for the top of the surface to...

https://www.bookmark-fuel.win/for-the-most-comfortable-reach-your-nightstand-should-sit-level-with-your

To get your bedside table height just right, aim for the top of the surface to sit level with your mattress or up to 10 cm below it. This makes reaching for your phone or a glass of water comfortable while you are lying down