About this tool
The Retirement Corpus Calculator estimates the lump sum needed at retirement to sustain your current lifestyle for the rest of your life, then computes the monthly SIP to reach it.
The model first inflates today's expenses to your retirement year, then capitalises those future expenses using a real (inflation-adjusted) post-retirement return so the corpus lasts through your life expectancy. The 25x to 30x annual-expense multiplier popularised by William Bengen and the Trinity Study is the global rule of thumb; Indian retirees typically lean toward 30x given longer post-retirement horizons and 6% baseline inflation. The accumulated EPF, NPS Tier-I, PPF, and existing equity mutual-fund balances should be subtracted from the gross corpus target to find the gap your monthly SIP must fund at your assumed pre-retirement equity return of 11-12% nominal.
How it works
- Enter current age, retirement age, and life expectancy.
- Enter current monthly expenses.
- Enter inflation (use 6%) and pre/post-retirement returns.
How to use the Retirement Corpus
The Retirement Corpus is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Retirement Corpus-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.
Frequently asked questions
How much corpus do I need at retirement?
Generally 25-30× annual expenses at retirement (inflation-adjusted). For ₹50k current monthly expenses retiring in 30 years: ~₹6-8 Cr needed.
What return to assume post-retirement?
Conservative 7-8% (debt-heavy portfolio for safety). Some keep 30% equity for inflation protection - then 9-10% works.
How does the 25x rule compare to the 30x rule?
25x annual expenses comes from the 4% safe withdrawal rate (Trinity Study) for a 30-year retirement horizon. 30x corresponds to 3.33% withdrawals and is preferred for 40+ year horizons, FIRE plans, or high-inflation markets like India where post-tax real returns are thinner. For Indian retirees retiring at 55, 30x is the safer planning multiple.
Should I include EPF, NPS, and PPF in my corpus calculation?
Yes, treat them as portfolio components with their own return assumptions. EPF and PPF currently yield 8.25% and 7.1% respectively and are tax-free at retirement. NPS Tier-I has 60% lump sum tax-free plus 40% compulsory annuity. Subtract these accumulated balances from the target corpus to find the gap your SIP must fund.
Is the Retirement Corpus accurate?
The Retirement Corpus applies the standard formula for retirement corpus. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Retirement Corpus free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
Can I use the Retirement Corpus on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum guidance.
How do I report a bug or suggest improvement to the Retirement Corpus?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours and update calculators when rules or formulas change.
How accurate is the Retirement Corpus?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Retirement Corpus free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Does the Retirement Corpus work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
Can I share results from the Retirement Corpus?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another retirement corpus tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.