How long will it take a moderate wrist sprain to heal?

Sprain to heal. It may be sore for several months but most injuries are healed within 6 weeks.
3-6 months. Wrist sprains come in various shapes and sizes. Most sprains will take 3-6 months to improve, though some can take longer. Be sure to obtain x-rays through your physician to rule out a fracture or more serious injury.