Corpus and monthly investment using an annuity over your lifespan and a perpetual model—not the 4% withdrawal rule.
Lifespan annuity
Perpetual (no 4% rule)
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This planner estimates corpus and monthly investment without the 4% rule: an annuity over your expected lifespan, and a separate perpetual benchmark (annual expenses ÷ post-retirement return) if you only spend portfolio returns.
Annuity corpus = present value of level annual expenses from retirement to lifespan at post-retirement return. Perpetual corpus = annual expenses ÷ post-retirement return. Inflation-adjusted (today's purchasing power) = nominal corpus at retirement ÷ (1 + inflation)^years to retirement. Monthly SIP solves for the payment (with step-up) that reaches each nominal corpus. While saving: monthly compounding on the SIP path.
Enter ages, lifespan, expenses, inflation, returns while saving and after retirement, and step-up. Compare the two corpus and SIP pairs; pick the story that matches how you plan to withdraw.
It sets how many years your retirement might last (from retirement age to that age). The calculator uses that horizon to estimate how large a corpus you need to fund steady expenses, using your assumed return on the corpus after retirement. Longer lifespan means more years to fund, so the required corpus tends to be higher.
We take your monthly expenses at retirement (today’s expenses grown by inflation) and treat them as a level stream over your retirement years. The required corpus is the present value of that stream at your post-retirement return — similar to pricing an annuity. It is a simplified model (no extra healthcare inflation, etc.).
This calculator does not use the 4% rule. It shows two approaches without it: (1) present value of your expenses over your expected lifespan (annuity), and (2) a larger perpetual corpus equal to annual expenses divided by your post-retirement return—if you spend only returns, principal stays intact.
Lifespan annuity is usually smaller: it assumes you can draw down principal over your retirement years. The perpetual number is higher: it assumes you only withdraw what the portfolio earns each year. Use the one that matches how you plan to draw down—or land between them.
It is the annual return you assume on your corpus once you stop working — for example lower if you move mostly to fixed income, higher if you keep a meaningful equity allocation. It affects how much you can safely withdraw each year relative to that corpus.
Inflation reduces the real value of your savings over time. The inflation-adjusted line shows the same corpus in today's purchasing power—so you can compare it to costs you know today.
You can add them as part of your overall retirement savings if you track them separately. Compare the suggested monthly investment to what you actually save across accounts.
Reduce the retirement age in the inputs. Earlier retirement means fewer years of saving, so you'll need a higher monthly investment or lower expenses to build enough.
Enter net expected returns if you want to account for fund management fees and taxes. The calculator does not separate them automatically.
Use these notes to stress-test the calculator, understand what drives the result, and choose the right tool for the decision you are making.
This planner assumes stable inflation, stable pre-retirement and post-retirement returns, and level real spending needs unless you change the inputs. It does not separately model healthcare inflation spikes, sequence-of-returns risk, pensions, or tax drag unless you bake those into your assumptions.
If retirement is 20 years away, today's monthly expenses of 60,000 will look much larger in nominal terms by the time you stop working. The calculator first inflates those expenses to retirement age, then estimates the corpus required under both a finite-lifespan and a perpetual-withdrawal style framework.
The annuity corpus is the more practical baseline if you expect to draw down principal over retirement. The perpetual corpus is a stricter benchmark that helps show how expensive it is to preserve capital while funding the same lifestyle.
Real retirement plans are rarely linear. Returns arrive unevenly, spending often changes after age 60, and healthcare costs can outpace general inflation. It is smart to test lower returns and higher expenses than your base case.
“The stock market is a device for transferring money from the impatient to the patient.”
— Warren Buffett
