For the best balance of comfort and style, your nightstand should sit level...

https://tango-wiki.win/index.php/Why_Do_Most_Bedside_Tables_Seem_to_be_60-63_cm_Tall%3F

For the best balance of comfort and style, your nightstand should sit level with your mattress top or just 5 to 10 cm below it. Most standard UK beds work perfectly with tables between 55 and 70 cm high