Keeper leagues
Keeper leagues usually let each team retain a limited number of players while the rest return to the draft pool. Commissioners may also assign draft-round costs or other keeper rules.
Dynasty leagues
Dynasty leagues keep most or all of the roster from year to year. New-player acquisition usually centers on rookie or prospect drafts, trades and waivers rather than a full annual redraft.
Draft-pick trading
Future draft-pick trading is much more common in dynasty because those picks are long-term assets. Keeper leagues may allow it, but it is less central to the format.
Roster depth
Dynasty rosters are usually deeper and may include taxi or prospect slots. Keeper formats generally stay closer to standard redraft roster sizes.
Which is better?
Choose Keeper if your group wants continuity without full long-term ownership. Choose Dynasty if your group wants multi-year team building, future picks and deeper roster strategy.
Related official rules
See the sport-specific formats for NFL Dynasty, NBA Dynasty, MLB Dynasty, NHL Dynasty, and the corresponding Keeper rules in each sport hub.