How long will your retirement corpus last? This calculator runs the math for any combination of corpus, monthly withdrawal, expected return on remaining funds, and inflation — showing the year your money runs out and how to extend it.
What is Retirement Withdrawal?
After accumulating a retirement corpus, the question shifts from 'how much do I save' to 'how much can I spend each month without running out?'. The answer depends on three things — corpus size, real return on the invested corpus, and inflation eroding withdrawals over time.
The standard rule of thumb is the 4% rule — withdraw 4% of starting corpus annually, increase by inflation each year, and the corpus lasts roughly 30 years. But this is US-centric and assumes specific historical returns. For India with higher inflation and different yield environment, a 3-3.5% real withdrawal rate is more realistic.
How withdrawal sustainability is calculated
Each month, the calculator subtracts your withdrawal from the corpus, applies the monthly return on the remainder, then increases next year's withdrawal by inflation. This continues until either the corpus reaches zero (you've run out) or 50 years pass (the practical horizon).
The output is the year the money runs out, the inflation-adjusted real withdrawal in the final year, and the maximum sustainable monthly withdrawal at which the corpus would last indefinitely (the 'safe withdrawal' rate).
- Bal
- Corpus balance—remaining money each month
- W
- Monthly withdrawal—with annual inflation step-up
- r
- Annual return—expected return on the invested corpus
How to use this calculator
Enter your retirement corpus
The total liquid amount available at retirement — PPF maturity, EPF, NPS lump-sum, mutual fund corpus, FDs, and any other investible assets. Don't include the home you live in or assets you can't liquidate.
Enter expected monthly withdrawal
What you actually plan to spend per month, in today's rupees. Calculator inflates this annually. Be honest — many retirees underestimate medical costs, which rise faster than general inflation.
Set the expected return
Conservative diversified retirement portfolio: 7-9% (FDs + senior citizen FDs + some debt funds + small equity allocation). Aggressive: 10-12%. Use 8% as a base case and stress test at 6%.
Set the inflation rate
India's long-run inflation has been 5-7%. For retirement planning use 6% as default. Healthcare inflation is closer to 10-12% — if a large portion of your spending will be medical, use a blended higher figure.
Read the longevity number
Calculator shows how many years the corpus lasts. If less than your expected lifespan (assume 90+), reduce withdrawal, increase return target, or top up corpus. The calculator also shows the maximum sustainable withdrawal that lasts indefinitely.
When to use it
Pre-retirement gap analysis
Run the calculator with your projected corpus at retirement and current monthly expenses inflated to retirement age. If the corpus runs out before age 90, you have a gap — either save more, retire later, or reduce expectations.
Determining safe withdrawal rate
The calculator's 'safe withdrawal' output is the monthly amount your corpus could sustain forever (corpus stays roughly stable). For India, this typically falls in the 3-3.5% annual range, lower than the US 4% rule.
Comparing retirement strategies
Run the calculator for different scenarios — full retirement at 60, part-time work to age 65, immediate annuity for 50% of corpus + invested rest. The longevity differences inform the best strategy.
Common mistakes to avoid
Using nominal returns and ignoring inflation
8% return looks fine until you remember 6% inflation eats most of it. Use real-return thinking — 8% nominal is roughly 2% real, which sustains only ~3-3.5% withdrawal rate.
Not factoring rising healthcare costs
Healthcare inflation runs 10-12% in India, twice general inflation. A retiree spending ₹10,000/month on healthcare today might spend ₹50,000 by age 80. Build a separate medical buffer or assume blended higher inflation.
Assuming you'll work part-time if needed
By 70-75, most people physically can't earn meaningfully even if willing. Plan as if you can't earn after retirement; if you can, that's a bonus.