What is the Retirement Calculator?
Retirement planning answers one question: how large a corpus do you need so that withdrawals plus growth fund your life from retirement to the end of the plan? The answer depends on four numbers — your current expenses, inflation between now and retirement, returns before and after retirement, and how long the money must last.
This calculator is for anyone from their 20s to their 50s setting a retirement target, early-retirement (FIRE) planners, and those coordinating EPF, NPS and mutual funds toward one goal. The uncomfortable insight is inflation: a ₹50,000/month lifestyle at age 30 becomes a ₹1.6 lakh/month lifestyle at 55 under 6% inflation.
The calculator computes the corpus as the present value of an inflation-growing annuity, then derives the exact monthly SIP needed to build it. The second insight is the cost of delay: starting at 30 versus 40 typically halves or quarters the required monthly SIP for the same corpus, because compounding does the heavy lifting that late starters must fund from salary.
Corpus as a growing annuity
Corpus = E × [1 − ((1+g)/(1+r))ⁿ] / (r − g)
| Symbol | Meaning |
|---|---|
| E | First-year expense at retirement (today’s expense inflated) |
| g | Inflation during retirement |
| r | Post-retirement portfolio return |
| n | Years in retirement (we plan to age 85) |
Worked example
Age 30, retiring at 55, spending ₹50,000/month today, 6% inflation, 12% pre-retirement and 7% post-retirement returns: first-year expense at 55 ≈ ₹19.3 lakh, corpus needed ≈ ₹2.9 crore, required SIP ≈ ₹15,300/month. Delay to age 35 and the SIP jumps to ≈ ₹28,000.
| Starting age | Required monthly SIP |
|---|---|
| 25 | ≈ ₹8,400 |
| 30 | ≈ ₹15,300 |
| 35 | ≈ ₹28,000 |
| 40 | ≈ ₹52,000 |
Benefits of the Retirement Calculator
Converts a vague anxiety into a concrete monthly number
Instead of worrying about “enough”, you get an exact SIP target to fund your desired retirement lifestyle.
Shows the true cost of delay in rupees
A 5-year delay can double the required SIP — the calculator quantifies exactly what procrastination costs.
Separates accumulation and withdrawal assumptions
You can model aggressive pre-retirement returns and conservative post-retirement returns independently.
Grounds asset allocation in a funded target
Knowing the corpus target tells you how much equity risk you need to take versus how much you can afford to hold in debt.
Coordinates multiple retirement vehicles
Subtract EPF and NPS projections from the target to find the gap your mutual fund SIP must fill.
Limitations to keep in mind
Sensitive to return and inflation assumptions
A 1% change in either assumption moves the corpus by lakhs; plan with a range, not a single number.
Cannot predict healthcare shocks or longevity
Medical inflation of 12–14% and living longer than 85 can both blow up a tidy plan — build buffers.
Assumes steady contributions through career breaks
A sabbatical or job loss interrupts the SIP; the calculator models a smooth path real life rarely follows.
Tax rules on withdrawals may change over decades
LTCG, annuity, and PF tax rules can shift over a 30-year horizon — revisit the plan every few years.
Does not model sequence-of-returns risk in retirement
A crash in the first retirement years is more damaging than the average return suggests; keep a cash buffer.
Common mistakes to avoid
Planning with today’s expenses
Inflation triples a lifestyle’s cost every ~19 years at 6% — always plan in future rupees.
Assuming equity-level returns after retirement
Sequence risk forces a more conservative post-retirement mix; plan with 6–8%, not 12%.
Forgetting healthcare
Medical inflation runs 10–14%; a dedicated health corpus or comprehensive insurance is non-negotiable.
Retiring the entire corpus into FDs
Over a 30-year retirement, inflation will halve the purchasing power of fixed income — keep a growth allocation.
Ignoring EPF and NPS in the target
Count your EPF/NPS corpus toward the target so your SIP only funds the gap, not the whole amount.
Expert tips for better results
Plan to age 90, not 85
Longevity is rising; planning 5 extra years adds a safety margin without dramatically raising the SIP.
Use 6% post-retirement return
Conservative post-retirement returns account for sequence risk and the need to hold more debt.
Keep a 2–3 year cash buffer at retirement
This lets you skip redeeming equity during early-retirement crashes, the most dangerous period.
Revisit the plan every 3 years
Inflation, returns, and expenses drift; a periodic recalculation keeps the SIP target honest.
Count EPF, NPS and gratuity toward the target
These are real retirement assets — subtracting them from the corpus needed shrinks the SIP you must fund yourself.
When to use this calculator
- Setting your retirement SIP amount
- Testing earlier or later retirement ages
- Stress-testing plans against higher inflation
- Coordinating EPF, NPS and mutual fund contributions toward one target
Frequently asked questions
Sources & references
- RBI — long-run inflation and interest rate data
- EPFO — Employees’ Provident Fund interest rate notifications
- PFRDA — National Pension System retirement rules
- WealthRise Methodology page — retirement corpus and SIP derivation