  We study the superconformal index of 6d SCFTs from their 't Hooft anomalies.
In the Cardy limit where the angular momenta on $S^5$ are large, we show that
the leading free energy, as well as a few subleading corrections, can be
computed from the 6d anomaly polynomials. Our large $N$ free energy accounts
for the entropy of supersymmetric black holes in dual $AdS_7$.
