SIP for Retirement: How Much to Invest Monthly and How to Build the Right Corpus

Most people who start a SIP for retirement do not have a clear number in mind. They are told to start as early as possible, invest regularly, and let compounding do its work. This is good advice in general, but it sidesteps the most important question: how much? Without a target corpus in mind, there is no way to know whether the Rs 5,000 monthly SIP you started at 28 is on track to fund the retirement you have in mind, or whether you will arrive at 60 with a corpus that covers three years of expenses rather than thirty.

This article works backward from the retirement outcome to the monthly SIP required. It sets out the framework for calculating a retirement corpus target, shows how different assumptions about returns, inflation, and retirement duration change that target, provides reference tables for different starting ages and income levels, and explains the adjustments that make a retirement SIP more robust than a static monthly contribution.

The numbers in this article are illustrative. Your specific target depends on your current expenses, the city you plan to retire in, your expected retirement age, your family situation, and your views on inflation. The framework, however, is applicable to anyone building retirement savings through equity mutual fund SIPs in India.

Step 1: Estimating How Much Corpus You Need

The starting point for any retirement SIP calculation is not the monthly investment. It is the corpus target: the total investable wealth you need to have at retirement to fund your desired lifestyle for the rest of your life without running out of money.

The most practical approach to estimating this corpus is the withdrawal rate method. You identify your annual retirement expenses in today's money, adjust for inflation to find what those expenses will cost in the year you retire, and then divide by a safe annual withdrawal rate to find the corpus needed.

The safe withdrawal rate is the annual percentage of your corpus you can draw down each year while maintaining a high probability of not depleting the portfolio over a defined retirement horizon. In India, a commonly cited starting point is 3 to 4 percent per annum, which means for every Rs 1 crore of corpus, you can sustainably withdraw Rs 3 to Rs 4 lakh per year. This rate assumes the remaining corpus continues to generate returns that partially offset inflation and the withdrawals.

The formula for estimating the corpus target is: annual retirement expenses in today's money, multiplied by the inflation adjustment factor to the retirement year, divided by the chosen withdrawal rate.

As an example: if your current monthly expenses are Rs 75,000 (Rs 9 lakh per year), you plan to retire in 25 years, and you assume inflation of 6 percent per year, your expenses in the retirement year will be approximately Rs 9 lakh multiplied by 1.06 raised to the power of 25, which equals approximately Rs 38.6 lakh per year. At a 3.5 percent withdrawal rate, the corpus needed is Rs 38.6 lakh divided by 0.035, which equals approximately Rs 11 crore.

Current Monthly Expense	Years to Retirement	Corpus Needed (3.5% withdrawal, 6% inflation)	Corpus Needed (3% withdrawal, 7% inflation)
Rs 50,000 (Rs 6 lakh p.a.)	30 years	Rs 6.2 crore	Rs 8.5 crore
Rs 75,000 (Rs 9 lakh p.a.)	25 years	Rs 11 crore	Rs 14.4 crore
Rs 1,00,000 (Rs 12 lakh p.a.)	25 years	Rs 14.6 crore	Rs 19.2 crore
Rs 1,00,000 (Rs 12 lakh p.a.)	20 years	Rs 10.9 crore	Rs 13.6 crore
Rs 1,50,000 (Rs 18 lakh p.a.)	20 years	Rs 16.3 crore	Rs 20.4 crore
Rs 2,00,000 (Rs 24 lakh p.a.)	25 years	Rs 29.2 crore	Rs 38.4 crore

Two observations from the table. First, the corpus requirements are large. An Indian salaried professional earning a reasonable income who wants to maintain their lifestyle in retirement needs a corpus of Rs 10 crore or more at retirement, which is a significant sum requiring serious systematic saving over decades. Second, the assumptions matter enormously.

A 1 percentage point difference in the inflation assumption (6 percent vs 7 percent) increases the required corpus by 37 percent for a 25-year horizon. The retirement planning calculation is extremely sensitive to the long-term inflation assumption, which makes sense because inflation compounds over decades just as investments do.

Step 2: Working Backward to the Monthly SIP

Once you have a corpus target, you can work backward to the monthly SIP needed to reach it, given an assumed annual return on the equity portfolio and the number of years to retirement.

The SIP future value formula gives the corpus accumulated after n months of investing an amount P per month at a monthly return r: FV = P multiplied by [(1+r) raised to n minus 1] divided by r, multiplied by (1+r). Rearranging for P gives the monthly SIP needed for a target FV.

For a more intuitive reference, the tables below show the monthly SIP required to reach specific corpus targets under different return assumptions, for investors at different starting ages assuming retirement at 60.

Target Corpus	Starting Age 25 (35 years to retirement, 12% return)	Starting Age 30 (30 years to retirement, 12% return)	Starting Age 35 (25 years to retirement, 12% return)
Rs 3 crore	Rs 1,600 per month	Rs 3,000 per month	Rs 5,700 per month
Rs 5 crore	Rs 2,700 per month	Rs 5,000 per month	Rs 9,500 per month
Rs 7 crore	Rs 3,700 per month	Rs 7,000 per month	Rs 13,300 per month
Rs 10 crore	Rs 5,300 per month	Rs 10,000 per month	Rs 19,000 per month
Rs 15 crore	Rs 8,000 per month	Rs 15,000 per month	Rs 28,500 per month
Rs 20 crore	Rs 10,700 per month	Rs 20,000 per month	Rs 38,000 per month

The table above uses a 12 percent per annum return assumption, which is approximately the long-term historical return of the Nifty 50 with dividends reinvested. The same calculation at 10 percent returns yields materially different numbers, as the table below shows.

Target Corpus	Starting Age 25 (35 years, 10% return)	Starting Age 30 (30 years, 10% return)	Starting Age 35 (25 years, 10% return)
Rs 5 crore	Rs 4,700 per month	Rs 8,400 per month	Rs 15,300 per month
Rs 10 crore	Rs 9,400 per month	Rs 16,800 per month	Rs 30,600 per month
Rs 15 crore	Rs 14,100 per month	Rs 25,200 per month	Rs 45,900 per month

The difference between a 10 percent and 12 percent return assumption on the monthly SIP required for a 25-year horizon is approximately 60 to 70 percent. An investor who assumes 12 percent returns but actually earns 10 percent will arrive at retirement with roughly 60 percent of the corpus they planned for. This is a material planning risk, and it explains why the SIP amount should be set conservatively, using a return assumption toward the lower end of the plausible range rather than the historical best case.

Using a return assumption of 10 to 11 percent rather than 12 to 13 percent for retirement SIP planning provides a meaningful margin of safety. If markets deliver the higher return, you retire with more than you need. If they deliver the lower return, you are still on track.

The Cost of Delay: Why Five Years Makes Such a Large Difference

The retirement SIP tables above illustrate the profound cost of delay. An investor who starts at 25 needs to invest Rs 5,300 per month to build Rs 10 crore by 60. An investor who starts at 30, just five years later, needs Rs 10,000 per month for the same outcome. An investor who starts at 35 needs Rs 19,000 per month. The required monthly commitment roughly doubles with each five-year delay, because the early years of compounding are the most powerful and cannot be recaptured by investing more later.

This is not a theoretical point. The first Rs 5,300 invested at 25 has 35 years to compound at 12 percent per annum, and grows to approximately Rs 2.1 lakh. The Rs 5,300 invested at 35 has only 25 years and grows to approximately Rs 64,000. The same amount invested 10 years earlier produces three times the terminal value. The first decade of investing is not the least important decade. It is the most important decade.

For investors who started late, the natural response is to increase the SIP amount to compensate. This works mathematically but requires a larger fraction of current income to be committed to retirement savings, which can strain household finances. The alternative, accepting a lower corpus target and planning for a more modest retirement standard or a later retirement age, is a legitimate planning response. What is not a rational response is to invest an insufficient amount and assume the market will make up the difference through exceptional returns.

The SIP Step-Up: How Annual Increases Transform the Outcome

A static monthly SIP, where you invest the same amount every month for 25 to 30 years, is the simplest structure but not the most effective one. Most investors' incomes grow over their careers, which means they can afford to increase their SIP amounts over time. A step-up SIP, where the monthly investment increases by a fixed percentage each year, dramatically improves the retirement outcome relative to a static SIP of the same initial amount.

Consider an investor who starts a SIP of Rs 5,000 per month at age 30. At 12 percent annual return over 30 years, this produces a corpus of approximately Rs 1.77 crore. If the same investor steps up the SIP by 10 percent each year, starting from the same Rs 5,000, the corpus at the end of 30 years is approximately Rs 5.4 crore: more than three times the static SIP outcome, for the same initial monthly commitment.

Initial SIP	Annual Step-Up	30 Years at 12% Return	Effective Final Monthly SIP Amount
Rs 5,000	No step-up (static)	Rs 1.77 crore	Rs 5,000
Rs 5,000	5% annual step-up	Rs 2.65 crore	Rs 21,600
Rs 5,000	10% annual step-up	Rs 5.40 crore	Rs 87,200
Rs 5,000	15% annual step-up	Rs 12.6 crore	Rs 3.26 lakh
Rs 10,000	10% annual step-up	Rs 10.8 crore	Rs 1.74 lakh
Rs 15,000	10% annual step-up	Rs 16.2 crore	Rs 2.62 lakh

The 10 percent annual step-up column is the most practically relevant. Salary growth in India averages 8 to 12 percent per annum for professional employees over their careers, meaning a 10 percent annual SIP increase is broadly achievable without reducing spending power. The investor who starts at Rs 5,000 and steps up 10 percent per year contributes Rs 21,000 per month in year 20 and Rs 87,000 per month in year 30. The total amount invested over 30 years is approximately Rs 98 lakh of principal, which grows to Rs 5.4 crore. The compounding on the increasing contributions is what drives the outsized outcome.

Setting up an annual SIP step-up is operationally straightforward with most Indian AMCs and investment platforms. When setting up the SIP, there is typically an option to register a step-up amount (a fixed rupee increase each year) or a step-up percentage (a percentage increase each year). Either approach achieves the objective. The simplest implementation is to review the SIP once per year, typically in April at the start of the financial year, and manually increase it in line with salary growth if the automatic step-up facility is not used.

Which Funds to Use for a Retirement SIP

The fund selection for a retirement SIP should be guided by the long time horizon, the compounding objective, and the need to manage risk as retirement approaches.

For investors more than 15 years from retirement, equity mutual funds are the appropriate primary vehicle. The long time horizon makes equity's short-term volatility manageable, and the higher expected return of equity relative to fixed income is necessary to build the large corpus that retirement requires. Within equity, a core allocation to diversified equity funds, whether Nifty 50 index funds, flexicap funds, or a combination of large and mid-cap funds, provides exposure to Indian growth without excessive concentration.

A simple, effective structure for a retirement SIP for a working professional more than 15 years from retirement might be: 50 percent in a Nifty 50 index fund, 30 percent in a flexicap or multi-cap active fund, and 20 percent in a mid-cap fund. This combination provides low-cost passive exposure to Indian large-cap equity, active management across the market cap spectrum, and some mid-cap growth without making the portfolio predominantly mid and small-cap.

As retirement approaches within 10 to 15 years, the portfolio should begin to transition toward a more conservative structure. This does not mean moving everything to fixed income suddenly; a 55-year-old with 5 years to retirement still has a 30-year investment horizon once they retire, so maintaining meaningful equity exposure is appropriate. The classic glide path approach reduces equity from 70 to 80 percent in the accumulation phase to 50 to 60 percent in the early retirement phase and 40 to 50 percent in later years.

NPS (National Pension System) is a tax-advantaged vehicle specifically designed for retirement that complements equity mutual fund SIPs. The NPS Tier 1 account offers a deduction of up to Rs 50,000 per year under Section 80CCD(1B) over and above the Rs 1.5 lakh Section 80C limit, which provides an immediate tax saving.

NPS has an equity option (under fund managers like SBI, HDFC, and others) that can be allocated up to 75 percent of the contribution for investors below 50. NPS and equity mutual fund SIPs serve different purposes but are complementary: NPS for the tax deduction and mandated retirement lock-in, equity SIPs for additional flexibility.

Years to Retirement	Suggested Equity Allocation	Fund Structure	Key Consideration
More than 20 years	80 to 90% equity	Heavy allocation to Nifty 50 index fund, flexicap, and mid-cap; small balance in debt funds	Maximise long-term compounding; short-term volatility is irrelevant at this horizon
10 to 20 years	70 to 80% equity	Core index fund plus active flexicap; begin reducing mid-cap; increase large-cap and debt allocation	Start building ballast against sequence of returns risk; maintain growth focus
5 to 10 years	55 to 70% equity	Shift toward large-cap and balanced advantage funds; increase debt allocation through short-duration or dynamic bond funds	Sequence of returns risk becomes more material; a bad market in the last 5 years can permanently impair corpus
Less than 5 years	45 to 60% equity	Large-cap, balanced advantage, and conservative hybrid funds alongside debt; avoid mid and small-cap	Preserve capital; smooth the transition into retirement drawdown phase

Common Mistakes in Retirement SIP Planning

• Not having a corpus target: Starting a SIP without knowing what corpus you need is like setting off on a long drive without a destination. You will not know when to stop, whether you are on track, or whether you need to adjust the route.

• Using too optimistic a return assumption: Planning for 14 or 15 percent annual returns in equity is not conservative. Historical returns of the Nifty 50 are approximately 12 percent per annum over long periods, and that includes some exceptional decades. Using 10 to 11 percent as your planning return and treating anything above that as a bonus is a safer approach.

• Ignoring inflation: A corpus that sounds large today may be insufficient in 25 years. Rs 5 crore in 2026 is not the same as Rs 5 crore in 2051 if inflation averages 6 percent over that period. The retirement corpus target must account for the real purchasing power needed at retirement, not the nominal amount.

• Not stepping up the SIP: A static Rs 10,000 per month SIP for 30 years will not build the same corpus as a stepped-up SIP starting at Rs 10,000 and increasing 10 percent per year. As income grows, the retirement SIP should grow proportionally.

• Cancelling SIPs during market corrections: The power of a long-term retirement SIP comes partly from buying more units when markets are down. Cancelling the SIP during a correction forfeits exactly the period when each invested rupee buys the most units and creates the most future value.

• Keeping all retirement savings in EPF and not supplementing with equity MFs: EPF returns (currently around 8 percent per annum) are valuable but may not be sufficient to build the equity-level corpus that retirement requires. EPF is debt-like in return profile. A retirement portfolio that includes equity SIPs alongside EPF captures the return premium of equity over long horizons.

• Not adjusting the SIP when significant life events change the financial picture: A promotion, a significant inheritance, a paid-off home loan, or children becoming financially independent all represent moments when the retirement SIP should be reviewed and potentially increased. These are inflection points that can significantly accelerate the corpus-building trajectory if acted upon.

The Sequence of Returns Risk: The Risk Nobody Plans For

Most retirement planning discussions focus on the accumulation phase: building the corpus. But there is a significant risk in the transition into retirement that is less widely understood: the sequence of returns risk.

Sequence of returns risk is the danger that a major market decline in the first few years of retirement can permanently impair the corpus, even if long-term average returns are exactly as planned. The reason is that early retirement withdrawals are made at the lowest point of the portfolio, depleting a larger number of units at depressed prices. The remaining portfolio then recovers, but from a smaller base, and may never fully compensate for the early loss of units.

Consider two retirees with identical Rs 10 crore corpora and identical 3.5 percent annual withdrawal rates. Retiree A experiences a 30 percent market decline in the first two years, then strong returns for the next 28 years. Retiree B experiences the same 30 percent decline but in years 27 and 28 instead of at the start. Retiree A may run out of money within 20 to 25 years despite the same average long-term return, while Retiree B is fine because the decline happens after 25 years of compounding on the full corpus.

Protecting against sequence of returns risk requires having two to three years of retirement expenses in conservative, low-volatility assets (short-duration bond funds, liquid funds, or a debt fund) at the point of retirement. This cash buffer means you do not need to sell equities during a market decline in the first years of retirement; you draw from the buffer while the equity portfolio recovers. This is one of the most important structural adjustments in the transition from accumulation to drawdown.

A Worked Example: 30-Year-Old Software Professional

To make the framework concrete, here is a worked example for a specific investor profile.

Profile: 30 years old, married, software professional in Bengaluru. Current monthly household expenses of Rs 1.2 lakh. Expecting to retire at age 60. Inflation assumption of 6 percent. Desired withdrawal rate of 3.5 percent per annum.

Step 1 (corpus target): Annual expenses today are Rs 14.4 lakh. At 6 percent inflation for 30 years, expenses in year of retirement will be Rs 14.4 lakh multiplied by 1.06 to the power of 30, which equals approximately Rs 82.7 lakh per year. Corpus needed at 3.5 percent withdrawal rate: Rs 82.7 lakh divided by 0.035 equals approximately Rs 23.6 crore.

Step 2 (monthly SIP for target corpus): At 12 percent annual return over 30 years, the SIP required to accumulate Rs 23.6 crore is approximately Rs 23,500 per month as a static SIP. With a 10 percent annual step-up, the initial SIP needed drops to approximately Rs 7,500 per month, increasing to approximately Rs 1.3 lakh per month in year 30.

Step 3 (fund allocation): Rs 3,750 (50 percent) in a Nifty 50 index fund, Rs 2,250 (30 percent) in a flexicap active fund, Rs 1,500 (20 percent) in a mid-cap fund. After age 45, begin transitioning the mid-cap allocation toward balanced advantage and large-cap funds. After age 55, maintain approximately 60 percent equity and 40 percent debt.

Step 4 (NPS supplement): Contribute Rs 50,000 per year to NPS Tier 1 under Section 80CCD(1B) for the tax deduction benefit, in addition to the equity SIP. At the new regime tax rate of 10 percent to 20 percent, or at the 30 percent old regime rate, the immediate tax saving of Rs 5,000 to Rs 15,000 per year from this deduction is itself a meaningful return.

Step 5 (annual review): Each April, increase the SIP by approximately the salary increment received. If a salary increment of 15 percent is received, increase the SIP by 10 to 15 percent. Avoid the temptation to consume the entire salary increment without increasing savings.

Disclaimer: This article is for educational purposes only and does not constitute financial or investment advice. All calculations are illustrative and based on assumed return and inflation rates that may differ materially from actual outcomes. Past returns of the Nifty 50 or any other index do not guarantee future performance. Retirement planning decisions depend on individual circumstances including income, expenses, family situation, health, and risk tolerance. Please consult a SEBI-registered financial adviser for personalised retirement planning advice.