Largest:
* Blue whale: The largest animal on Earth, reaching up to 100 feet long and weighing up to 200 tons.
* Fin whale: The second largest, reaching 85 feet long and 40-80 tons.
Medium-Sized:
* Humpback whale: About 40-50 feet long and 25-40 tons.
* Sperm whale: Up to 60 feet long and 40-45 tons.
* Gray whale: About 40-50 feet long and 15-35 tons.
Smaller:
* Minke whale: About 30 feet long and 10-15 tons.
* Sei whale: About 50 feet long and 20-30 tons.
* North Atlantic right whale: About 45-55 feet long and 40-65 tons.
* Beluga whale: About 13-16 feet long and 1.5-2 tons.
Smallest:
* Dwarf sperm whale: About 6-8 feet long and 300-700 pounds.
Important Note: This is just a general overview. There's a lot of variation within each species, and some whales can grow to be larger than others.
Let me know if you'd like more specific information about a particular whale species.