The heaviest dinosaur is generally considered to be Argentinosaurus huinculensis , though the exact number is debated because the fossils are fragmentary. Estimates put it at roughly 60 to 124 tonnes , with many paleontologists favoring the lower end of that range.

Quick Scoop

  • Likely heaviest: Argentinosaurus huinculensis
  • Estimated weight: about 60–124 tonnes
  • Why it’s uncertain: the remains are incomplete, so weight estimates vary a lot

A nearby contender

Some sources point to Dreadnoughtus as one of the best-supported giants, with an estimate around 59 metric tons and unusually reliable calculations from more complete remains.

Bottom line

If you want the most widely cited answer , it’s Argentinosaurus. If you want the best-documented massive dinosaur , Dreadnoughtus is often mentioned as a strong contender.