The SAT takes 3 hours, excluding the SAT essay. It has three parts: Reading, Writing & Language, and Mathematics. All of these sections have time allocated for them: Reading 65 minutes, Writing and Language 35 minutes, and Math 80 minutes. Another 50 minutes is added by an optional essay that some colleges might use, making the overall length of the test 3 hours and 50 minutes.

To know more: https://metaapply.io/blog/how-long-is-sat/