How big a corpus you need on retirement day, and what monthly SIP (on top of whatever you already have) gets you there. Inflation isn't a footnote — it's the difference between ₹1 lakh a month today and the four-times-larger spend you'll have at retirement.
Step 1. Your spend today grows at inflation until retirement. ₹1L/month today is roughly ₹4.3L/month after 25 years at 6%.
Step 2. The corpus you need on retirement day is the present value of a monthly annuity paying your future monthly spend for the post-retirement window. We discount at the real return (post-retire return minus inflation) so the corpus keeps pace with rising costs through retirement, not just at it.
Step 3. Subtract what your current corpus will grow to (at pre-retirement return) and we solve a standard SIP equation for the monthly contribution that bridges the shortfall. Full methodology · reviewed January 2026.
Educational projection only. MintByte is an AMFI-registered mutual fund distributor (ARN-314872); SEBI Registered Investment Adviser and Research Analyst registrations are in process. Not investment advice.