How old do you have to be to legally have sex?

No law on when you can have sex. If you think you are old enough and want to you can. The age of consent is a different thing. Depends on the state but most is age 18 and that means if you are 18 or older you cant have sex with people younger than 18

The legal age to have sex varies from state to state some are 14 some 15 some 16... If the legal age in the state is 15 then that means a 15yo can have sex with a 15,16,or 17yo. but no one under 15..

Differs in countries, some are 16, some are 18. Disclaimer: I am not a lawyer so these are just what I think are correct

Around 16 17 18 depends on the country

Differs