What are the chances of getting pregnant after unprotected sex?

Age-dependent. Your age is a major determinant; the chance may be as high as 25% in your teens and twenties, but decreases to <5% after 40. It also depends on when during your cycle you have vaginal intercourse; most likely to conceive around 10-16 days after the first day of your last period (assuming regular 28-day cycles).
Varies. Pregnancy can occur even with "protected" sex. If you do not desire pregnancy talk with a doctor about options of birth control.
20% at most. If you and the man are the 2 most fertile folks on the planet, and you had unprotected sex at the time of ovulation, you have about a 1 in 5 chance on conceiving.

Related Questions

What are the chances of me getting pregnant, after unprotected sex, five days before I start ovulating?

Good chance . Anyone having intercourse without birth control or condoms may get pregnant. If intercourse was within 72 hours you consider taking plan b. Ella (ulipristal acetate) is another brand that can be used up to 5 days after unprotected intercourse. Plan b is a high dose of birth control to disrupt the hormonal patterns to delay or prevent ovulation. Abnormal bleeding after is common. Check preg test in 10 days. Read more...

I want to get pregnant... I have unprotected sex everyday what is my chance of getting pregnant?

TTC. If 19 is your correct age, and if you and your partner have no fertility problems then your chance is roughly 20% per cycle and around 85-90 % in one year. Read more...