For the perfect setup, aim for your bedside table to sit roughly 5-10 cm below...

https://www.stealth-bookmark.win/for-a-comfortable-reach-your-nightstand-should-sit-level-with-the-top-of-your

For the perfect setup, aim for your bedside table to sit roughly 5-10 cm below the top of your mattress. This makes reaching for your phone or a glass of water comfortable rather than a stretch