Torpedo yields are all over the place; you'd probably get a different number from every single example of one exploding in the whole of Trek.
I know. Yields go from few kilograms of TNT to few hundred megatons / few gigatons of TNT, but we have relatively few instances where they specifically stated torpedoes are on full yield, or it can be concluded torpedoes are full-yield. And some of these instances can be explained in several possible ways (like "Pegasus" - can be interpreted to give few kilotons to 500 megatons as high end for torpedoes). But Manuals are not canon anymore, and trying to fit Manuals in overall picture only unnecesarily complicates things.