Hi . It is clear that you are concerned and it is good that you sought out a place you can get information. I need to note that we are not medical professionals and, for your protection, cannot provide medical advice over the internet. I do want to share with you this article from our editorial team on HIV transmission risk: https://h-i-v.net/transmission-risks. You will note that the estimated risk for insertive penile-vaginal intercourse is 0.04 percent. It is important to note that these are estimates, so individual circumstances can alter an individual's risk in a given case. Of course, the only way to be certain is testing and this article provides information on the various types of tests and their window periods for effectiveness: https://h-i-v.net/test-types. I also want to note that, if your encounter was in the last 3 days (72 hours) you may be eligible for PEP (post-exposure prophylaxis). As this overview article notes, "PEP is an effective way to prevent HIV after a single, unexpected exposure:" https://h-i-v.net/pep. If potentially eligible, a medical provider should be able to provide further information. Hope this information is helpful. Best, Richard (Team Member)