Retirement Calculator

Retirement is really two separate problems chained together: what will your monthly expenses cost by the time you retire, and how large a corpus do you need at that point to fund them for the rest of your life.

For the first, we inflate today's monthly expense forward using your current age and retirement age: Future expense = Today's expense × (1 + inflation)ⁿ. For the second, we treat retirement as an annuity that has to last from retirement age to life expectancy, discounted at the real return during retirement — the post-retirement return adjusted for inflation using the Fisher equation — since your expenses will keep rising with inflation even after you stop earning.

Finally, we solve for the monthly SIP, from today until retirement, that reaches that corpus at your assumed pre-retirement return — the same annuity-due formula used by the SIP calculator, run backwards from the target.