Three time windows to reinvest: (1) Buy new property 1 year BEFORE the old property sale, the earlier purchase already counts. (2) Buy new property within 2 years AFTER sale. (3) Construct a new property within 3 years after sale. ALL three qualify. CGAS, the safety net: If you have sold the property but haven't yet bought a new one before your ITR filing deadline (July 31 or October 31), deposit the LTCG amount in Capital Gains Account Scheme at any nationalised bank (SBI, PNB, Bank of Baroda etc.) in a designated CGAS account. You can then withdraw from CGAS to fund the new property purchase within the 2/3 year window. CGAS deposit must happen BEFORE filing ITR to claim the exemption in the sale year. Partial exemption: If only part of LTCG is reinvested: exemption = (new property cost / LTCG) × LTCG.