In Battle Of Gods, Bulma accidentally says she's 38.
But that has to be a mistranslation (Mai says she's 31 in that movie, which is WAY off). In Goku's case: He's 12 during the 21st Martial Arts Tournament, three years pass between that and the 22nd which makes him 16 there, 19 at the end of Dragon Ball, 20 at Gohan's birth, and 24 at the beginning of the Saiyan Saga. Counting all the years he's been dead, he's 25 during Namek, 26 at Trunks, 29 at Androids / Cell, and 36 for Buu.
Add the 3.5 year time-skip between the end of Z and the beginning of Super, that would indeed make Goku 39 and Bulma 43.