TreasuryDirect. It shows the rates for both kinds of bonds. Today's Ibonds have a real yield of 0.00% and are expected to keep at that rate for a while. The variable yield is based on inflation, which was very high but has been much more muted for the past several months. That flashy 9.62% is going to be much much lower when it swaps.
TIPS currently have a nonzero real yield.