Hi, thanks for using Hebcal!
Please double check your location (Diaspora vs Israel) and what setting you selected in Hebcal.
If you are located in Israel, Shmini Atzetet and Simchat Torah occur on the same day (the 22nd of Tishrei)
If you are located in the Diaspora, Simchat Torah follows Shmini Atzetet on the 23rd of Tishrei
Shana Tova and G'mar Chatima Tova!
Customer support service by UserEcho