Is a hcg level of 512 at 5weeks ok?

HCG: One HCG result cannot in any way be used to reassure you. That would be impossible. HCG changes and the changes are what tell us if the pregnancy is healthy or not. 512 seems very low.

Yes: This varies amongst women. A normal level at 5 weeks is anywhere between 18 and 7,340. As long as you're having an appropriate rise in your HCG level (doubling every 48-72 hrs), then there's nothing to worry about. There's no need for you to continue checking your HCG level, however, unless you have concerns for miscarriage or your doctor recommends it. Congrats on your pregnancy!