Confused somebody help

If you can't get pregnant when you're not ovulating then why on normal days on glow does it say it's a 3% chance or getting pregnant? And I know sperm can live in you from 3-5 days but even more than that many days away from ovulation it says 3% chance which is very small but still possible... and is also says that on the days after? I'm just confused, why does it say that if you can't or is it just very unlikely?