How long does it take for birth control to be effective?

Depends. It depends on which birth control method you're talking about. If you're talking about birth-control pills 7 to 14 days is reasonable.

Related Questions

How long does it take until birth control pills are effective after waiting 1 week to start a new pack? Is it immeadiately or does it take a few days?

Bcp. Birth control pills are usually effective the first month you begin taking them. To be safe, some doctors recommend the use of another form of birth control, such as condoms and foam, during the first month. After the first month, you can just use the pill for birth control. Read more...
It depends. It depends on whether you can be sure you're not pregnant--no sex in the last month, consistent birth control. If no risk of pregnancy, you can do a "quick start" and start anytime. Many doctors advise starting on the first day of a period. Use back up birth control for 7 days if you start anytime other than day 1 of your period. Read more...

How long does it take for oral birth control to be effective?

Immediately if... I usually recommend to pts to start their pill on day one of their cycle. If done this way, and it is truly your normal menses, the pill should protect you from pregnancy right away. Read more...

How long does it take for a birth control pill to be effective?

Effectiveness of BCP. It takes about 2 weeks for a bcp to be effective if you've started soon after your menses. Nevertheless, i advise my patients to use condoms the first month, and to rely on the bcp the second months. Read more...