I found out on a HPT at 4 weeks 2 days (when my period was past due), but I made myself wait until then to test.

Really, I *knew* from just after I conceived, I dreamt about it a couple of times out of the blue and I had been getting a couple of symptoms from just before my period was due. The HPT was really just to confirm for DP!

Like Delta, my GP didn't bother to do another test as he said HPTs were so accurate.