How much does a big pony weigh?

The amount of weight a pony can take when ridden depends entirely on its size and breed, health and stamina. It's a subjective question.

Depending on the breed and age miniature pony's/common dwarf horse (standing at 24-32 inches high at the shoulder can safely carry between 30-60 Lbs. which is roughly the average child up to 10 years old...

Depending on breed and age,the average size pony standing at 40-58 inches high at the shoulder (mostly seen at fairs and carnavals for pony rides) can safely carry between 100-175 Lbs,There are also other pony breeds that are more stocky and muscular that can safely carry 200-250 Lbs....