The golden rule for bedside tables is comfort and accessibility. Aim for a...

https://www.acid-bookmarks.win/to-get-the-perfect-bedside-table-height-aim-for-your-nightstand-to-sit-roughly

The golden rule for bedside tables is comfort and accessibility. Aim for a height that sits between 5 and 10 centimetres below the top of your mattress. Most UK beds work best with tables in the 55 to 70 centimetre range