Radio Spectrum Inventory Act

Radio Spectrum Inventory Act - Amends the National Telecommunications and Information Administration Organization Act to require the National Telecommunications and Information Administration (NTIA) and the Federal Communications Commission (FCC) to: (1) create and maintain an inventory of each radio spectrum band of frequencies listed in the United States Table of Frequency Allocations from 225 megahertz to, at a minimum, 3.7 gigahertz, and to 10 gigahertz unless the NTIA and the FCC determine that the burden of expanding the inventory outweighs the benefit; (2) create a portal or website to make the inventory available to the public; and (3) report to Congress.

Requires a report by the NTIA and FCC to Congress on which spectrum, if any, should be reallocated or otherwise made available for shared access.

Creates exceptions to the inventorying, public disclosure, and reporting requirements of this Act, including exceptions relating to: (1) national security, homeland security, and public safety; and (2) confidential and proprietary information.