Work out how much of your house rent allowance is exempt under the old regime.
Exempt HRA = least of: actual HRA; 50% of salary in a metro (40% elsewhere); rent paid − 10% of salary. Salary = basic + DA.
Salary ₹6,00,000, HRA ₹3,00,000, rent ₹2,40,000 in Pune (metro from FY 2026-27): exempt ₹1,80,000.