The whole thing depends on when the female ovulates. The egg must be in the right position in the uterus for fertilization to take place. No egg, no pregnancy. Sperm are able to live in the female for about 48 hours. Figure your ovulation time, entry of the sperm and shelf life of the sperm to get a more definitive answer!
When you get pregnant not every womens body is completely the same. Some women it can take as soon as you have sex
How Long Does it Take to Get Pregnant
How Long Does it Take to Get Pregnant
If she is pregnant, it can show up a positive result within days. If there is a possibility, she may be pregnant there are Home Pregnancy Tests, that detect it as early as the first day of her missed period, she can also have blood work done, that will show I believe almost right away. Hope this helps. Good-Luck.
Well it could take a matter of minutes, if she is ovulating at the time. It is possible for sperm to stay alive for up to 7 days in your body, so anything longer than a week is really unlikely.