i was just wondering when they are there full height because i have a 5 month old pup and it just keeps on growing. i was just wondering when will it stop.

Hi,
I don't know about bullmastiffs in particular, but most medium/large breeds reach their full height at about 10-12 months and then start to fill out, and reach physical maturity at about 2 years.

I believe the height range for bullmastiff dogs is 25-27 inches and bitches 24-26 inches. (Always measured at the shoulder.)

Hope this helps. :)