1.你几岁啦?or 你多大啦?( when addressing to a little child)
2.你多少岁?or 你多大?(when addressing to someone about your age)
3.您今年贵庚?(we seldom use this expression nowadays, but still you may see it in some articles, and it is used when addressing to someone old)
4.您老今年高寿?(when addressing to someone old)
还有 芳龄(of a girl),高龄(of an elder),也会用……