How long does it take to heal a soft pelvic fracture?

8-12 weeks: Fracture of the pelvis heal fast.

6-12 weeks: I am assuming you mean a small crack to the pelvic bones. Nondisplaced, or minimally displaced pelvic fractures usually heal within 6-12 weeks. During that time, you should refrain from heavy lifting and stair climbing. But low impact exercises such as walking, or swimming should be encouraged as tolerated.