Yes, wizards/witches seem to age slower than muggles. It's like the opposite of how dog years work with humans.

Dumbledore was around 150 years old when the series started. That would make him 156 when he died.

Rubeus Hagrid was born December 6, 1928. Hagrid was a student at Hogwarts School of Witchcraft and Wizardry at the same time as Tom Riddle. Presumably Hagrid's first year would be 1940, as this would place him at the correct starting age, eleven. Rowling has stated in an interview that Hagrid was in Gryffindor house.

Tom Marvolo Riddle (Voldemort) was born on December 31, 1926. Riddle attended Hogwarts from 1938 to 1945. He was in his 5th year when he had Hagrid expelled during his (Hagrid's) third year after he was accused of opening the Chamber of Secrets (which Riddle was actually responsible).

That makes Hagrid around 78 years old during the last book and Voldemort around 80. Give or take a year (I really suck at math).