How big does a butterfly grow to?

It depends on the species. Queen Alexandra's Birdwing butterfly is the largest butterfly in the world with the female reaching a wingspan of 31 cm.

Answer:Female Queen Alexandra's Birdwings, the largest butterfly, can reach a wingspan of 12.2 inches and a body length of 3.2 inches
It depends on the species. Some can be as big as a dinner plate !
It depends on the species. Queen Alexandra's Birdwing butterfly is the largest butterfly in the world with the female reaching a wingspan of 31 cm.
Butterflies are all different sizes. The biggest butterfly is the Queen Alexandria Birdwing. The butterfly has a wingspan of 11 to 12 inches.
Butterflies don't grow, when they come out of the chrysalis and stretch their wings, that's it.

The largest butterfly variety is in Papua New Guinea, and it's got a wingspan of 1 foot.

It is known as the Queen Alexandra's birdwing