Calculating HRA exemption accurately is not easy. To summarize, HRA exemption is calculated as the least of the following - The amount actually paid as HRA. Rent paid minus 10% of the basic salary. 50% of the basic salary if the rented accommodation is in a metro city, and 40% otherwise. These rules are simple enough, but it can get a little complicated when a payroll platform like Opfin tries to calculate the HRA exemption for the entire year.