For a comfortable bedroom, your nightstand should sit level with the top of...
https://spark-wiki.win/index.php/Two-Drawer_vs_Three-Drawer_Bedside_Table:_Which_Height_Works_Best%3F
For a comfortable bedroom, your nightstand should sit level with the top of your mattress or just 5-10 cm lower. This makes reaching for your phone or a glass of water effortless while you are in bed