This is to help people with frog or toad. Most of these ways to distinguish the two work well but there are still some toads that look like frogs and vice versa.
Tips that work
One of the best ways to tell if its a frog or a toad is to look for a parotoid gland. Its usually behind the head.
I circled it on the Cane toad. This gland produces the toxins in the toads. It is only on toads.
Next way is to check for warts. Toads usually have warty skin or bumpy skin while frogs are usually smooth.
The skin of this toad is really dry while there are bumps all over it. There are giant warts on its back. You can also see the parotoid gland easily.
Tips that don’t work so great but can help a bit
Another way is to look at how long the legs are on the amphibian you are looking at. Frogs generally have longer upper legs to help jump farther.
The upper leg on this Green frog is a lot longer than any of the toads before it.
Toads typically have more compact body size compared to frogs but that’s not always the case.
Frogs usually have more bright colors than toads.
So here’s a frog or toad example
So it has bright colors and a compact body, these signs both point at it being a frog or a toad. So now I look at the skin and I don’t see warts and just a few bumps. I’m leaning more towards frog. I look for the parotoid gland and I don’t see one. I’m still leaning frog. The upper legs don’t look too long so that doesn’t help. Overall, I would say frog and I would be right. It is the Malagasy Rainbow Frog (Scaphiophryne gottlebei).