Why your yasmin birth control pills has 21 tablets only?

You have the option of buying Yasmin 28 pills or 21. The 21 pills option simply doesn't have the 7 last sugar pills that are just there for a reminder to take your pill everyday. So if you have the Yasmin 21 tablets and are done with the last pill in your pack, you don't take any pill for 7 days, then start in a new Yasmin 21 pack.