A toad can live up to 2 months with out any food. But make sure to at least check on them to make sure that they have no difference in their behaviour.
most likely 4-6 weeks!!!
did some research on people who have gone without food for extended periods of time:
Medical Doctors Commonly cite 4 to 6 weeks without food
10 Political...
I am not sure how long toads can survive without food but i have four (pip squeak dragonfly and dragon) and i feed them weekly. they do fine but i suggest also taking toads outside to exercise and...