Plan B® is currently FDA approved for use up to 72 hours (3 days) after unprotected sex. Ella® is FDA approved for use up to 120 hours (5 days) after unprotected sex.
Most research shows that overall, ella® is more effective than Plan B® for most women. ella® is equally effective throughout the 5 days after unprotected sex, but Plan B® is less effective with time (ex. more effective at 24 hours than after 48 hours).