The true limit of his strength is unknown, but he has proven able to beat the Rhino unconscious and to hold his own against three Spider-Men at the same time (Peter Parker, Ben Reilly, and Spidercide). Kaine's durability is also superior to Spider-Man's, as he was able to withstand a massive explosion without any form of discomfort. He also tanked a full power blow from Spider-Man, without so much as flinching, as well as a bullet to the shoulder which barely slowed him down.