How old do I have to be to stay home alone?

At around age 12 you can start being home alone for a few minutes to around an hour.
Then increase the time over the years.
Basically it is up to your parents.

That depends on your parents and on the laws where you live.

The legal age in most places to babysit is 12, so I would think that you could start staying home alone at 12 years of age.

That depends on mom and dad though.

My older boys were about 12 when they stayed alone after school for ahour or two.

They were 14 before they stayed any evenings alone at home.
** and they of course proved it was too young on some evenings