For a perfect setup, aim for your nightstand to sit level with the top of your...

https://mike-wiki.win/index.php/What_is_the_Average_Bedside_Table_Height_in_the_UK%3F_A_Professional_Guide

For a perfect setup, aim for your nightstand to sit level with the top of your mattress or just 5-10 cm lower. This ensures you can reach your glass of water or phone easily without straining. Most UK beds work best with a table height between 55-70 cm