You want to measure centre to centre, ie from the centre of the seat tube to the centre of the head tube, this cancels out any variation in tube diameter. The size of the bike, your height and inseam might help, or at least people with similar dimensions might be abel to offer advice.
Also, what makes you think it isn't right? Sore hands, too upright, etc. Some problems can be solved with a different setback of the saddle for instance.