For the most comfortable setup, aim for your bedside table to sit roughly 5-10...

https://www.play-bookmarks.win/for-the-perfect-reach-your-bedside-table-should-ideally-sit-5-10-cm-below-the

For the most comfortable setup, aim for your bedside table to sit roughly 5-10 cm below the top of your mattress. This makes it easy to reach your phone or a glass of water without straining your arm