Do you need an International Driving Permit for Brazil?

This is the one destination where we will not give you a clean answer, because the reputable sources contradict each other.

AAA and several US government pages state that Brazil accepts the Inter-American Driving Permit (IADP) and not the standard International Driving Permit. Against that, Brazil is a party to the 1968 Vienna Convention on Road Traffic, which provides for recognition of the IDP, and the IADP-only claim is documented as a long-running misconception propagated through US sources.

The likely origin of the confusion is that the United States signed the 1949 Geneva Convention but not the 1968 Vienna Convention, while Brazil did the reverse.

Until you can confirm with a Brazilian consulate, the conservative choice is to carry the IADP, which AAA issues. It costs the same as an IDP and removes the ambiguity.

An International Driving Permit is a translation of your licence into a standard multilingual booklet, issued under the 1949 and 1968 road traffic conventions. It is not a licence, and it is never valid on its own: you carry it with your own licence, and police expect to see both.

It is issued against the vehicle classes already on your home licence, and it never adds one. If your licence does not cover motorcycles, an IDP does not let you ride a scooter in Brazil; if it does not cover a heavier vehicle, the permit will not cover a camper or a minibus either. The permit restates what you already hold, in a form the local authorities can read.