It usually takes 5 to 14 days to recover from a grade one ankle sprain. This is when slight stretching and damage occurs to the ligaments. With a grade one sprain, there is slight instability, pain, swelling, joint stiffness, and trouble walking. Grade two sprains can take 4 to 6 weeks to heal. This involves partial tearing of the ligaments. Signs of a grade two sprain include instability, moderate to severe pain, swelling, stiffness and possible bruising. Grade three sprains can take 8 to 12 weeks to heal. This is a complete tear of the ligament.