Emergency contraceptives are about 58-94% effective at preventing pregnancy. The range is so large because when taken at the right time, emergency contraception is very effective. However, some women are unable to access the medication until it’s almost too late.
Ella® is slightly more effective than Plan B®. Plan B® is more effective the faster you are able to take it (for example, it’s more effective if taken 3 hours after unprotected sex rather than 48+ hours after).