You ejaculated on your girlfriends vagina but not in it can she get pregnant if yes What is the chance off this happening?

There is a definite possibility of a pregnancy, but there are other factors at hand too.

If this was done at the correct time for her to actually conceive, then I would count on a 15-25% chance.

I have however not been able to actually find statistics for this on the internet.

If you however did have unprotected intercourse and then pulled out and ejaculated on her vagina, then the chances are higher if everything else is time wise right.

We men release sperm before the actual ejaculation in most cases.

Remember.. It only takes one of them.