When the pill is taken correctly with perfect use, it’s over 99% effective at preventing pregnancy.
Fewer than 1 in 100 women who take the pill as a method of contraception will get pregnant within a year.
No contraception is 100% reliable, and the effectiveness of the pill can lower if you miss a pill, are taking certain antibiotics, or have vomited or had diarrhoea shortly after taking the pill.
With typical use, meaning you occasionally miss a pill, your contraception is around 91% effective, with 9 in 100 women becoming pregnant within a year.