how old does a senator have to be?

best answer
The Constitution r eads “No Person shall be a Senator who shall not have attained to the Age of thirty Years and been nine Years a Citizen of the United States and who shall not when elected be an Inhabitant of that State for which he shall be chosen.” From this one can see that the answer to the question of how old one must be to be a senator in the United States is a minimum of 30 years old.