Generally, weapons grade fissile material is about 93% enriched, but:
FYI, people: 20% enriched U-235 is sufficient to create a bomb that will ignite an uncontrolled chain reaction, if the right bomb geometry is used and if you are willing to accept a larger bomb that may be delivered by train or ship, instead of a missile or aircraft!
My understanding is the jump from 20 to 93 is easier than going from 1 to 20.
I could be wrong.