Retirement SIP Calculator

Why retirement planning needs SIPs

Retirement in India is fundamentally different from retirement in the West. There is no government social security worth the name — the EPS pension tops out at a few thousand rupees a month even for long-tenured employees, and the NPS default annuity rates barely beat inflation. The joint family system, which once provided a natural safety net, is fast disappearing in urban India. Combined with rising life expectancy (an urban Indian who reaches 60 can expect to live to 80–85), this means retirement is now a 25–30 year financial project that you must fund yourself.

At the same time, inflation silently erodes purchasing power. India has run at 5–6% CPI inflation for two decades; even at 5%, a rupee today will buy what ₹3.4 buys in 25 years. If you spend ₹50,000 a month today and want the same lifestyle in retirement 30 years from now, you will need roughly ₹2.87 lakh per month at that point. Most middle-class families drastically underestimate this number, save too little, and discover the gap too late.

A retirement SIP is the most practical answer. By investing a fixed monthly amount over 25–35 years of working life, you let compounding do the heavy lifting — equity mutual funds have delivered 11–13% CAGR over long periods in India, and a 30-year SIP at 12% turns every ₹1 invested into roughly ₹35. Use the SIP Calculator to model the forward direction (given a SIP, what corpus) and this retirement SIP calculator for the backward direction (given a goal, what SIP).

How the Retirement SIP Calculator works

The calculator takes seven inputs. Current monthly expenses represent your household expenditure today — the lifestyle you want to maintain in retirement. Current age and retirement age define your accumulation phase. Life expectancy defines your distribution phase — and it should be set generously, because outliving your money is the worst outcome. Pre-retirement return is what your equity-heavy SIP will earn during accumulation (11–12% is reasonable). Post-retirement return is what your debt-heavy corpus will earn during retirement (6–7% for a conservative debt portfolio). Inflation drives both expense growth and the real-return calculation.

With these inputs, the calculator does three things in sequence. First, it inflates your current monthly expenses to the year of retirement — so a ₹50,000/month lifestyle today becomes ₹2.87 lakh/month at retirement in 30 years at 6% inflation. Second, it computes the corpus needed at retirement as the present value of an annuity that pays inflated annual expenses for the entire retirement period, discounted at the real post-retirement return (nominal return minus inflation). Third, it solves for the monthly SIP that will accumulate to that corpus during the working years, using the standard annuity-due formula. The result is one number: the monthly SIP you need to start today.

Pair this calculator with the SIP Goal Calculator for a sanity check on the corpus, the SIP Inflation Calculator to see how inflation erodes nominal returns, and the SWP Calculator to plan the withdrawal phase. The Step-up SIP Calculator shows how annual step-ups dramatically lower the starting SIP — read the section below.

The math: future expenses, corpus, and required SIP

Three formulas drive the calculator. The first inflates your current monthly expenses to the year of retirement:

Monthly Expenses at Retirement = Current × (1 + inflation)^Years to Retire

The second computes the retirement corpus using the present value of an annuity, discounted at the real post-retirement return:

Corpus = Annual Expenses × [1 − (1 + r_real)^−Years in Retirement] / r_real

where r_real = post-retirement return − inflation (in decimal). The third computes the required monthly SIP using the future value of an annuity due:

P = Corpus / [((1 + r)^n − 1) / r × (1 + r)]

where r is the monthly pre-retirement return (annual ÷ 12) and n is the number of months to retirement.

A worked example. Suppose you are 30, plan to retire at 60, expect to live to 85, spend ₹50,000 per month today, and assume 12% pre-retirement return, 7% post-retirement return, and 6% inflation. Years to retire = 30; years in retirement = 25. Monthly expenses at retirement = ₹50,000 × (1.06)^30 = ₹2,87,175. Annual expenses at retirement = ₹34,46,100. Real post-retirement return = 7% − 6% = 1%. Corpus = ₹34,46,100 × [1 − (1.01)^−25] / 0.01 = ₹34,46,100 × 22.02 ≈ ₹7.59 crore. Required monthly SIP at 12% for 360 months = ₹7.59 crore ÷ 3530 (the annuity-due factor) ≈ ₹21,499 per month. Over 30 years you will invest roughly ₹77.4 lakh; the remaining ₹6.8 crore of the corpus comes from compounding.

The same math scales for any lifestyle. A ₹1 lakh/month lifestyle today (a comfortable metro middle-class existence) needs a corpus of around ₹15 crore and a monthly SIP of around ₹43,000 — well within reach for a 30-year-old earning ₹2 lakh/month. But push the start to age 40 and the SIP more than doubles. Starting early is the single biggest lever you have.

The 25x rule and the 4% safe withdrawal rate

A popular rule of thumb, originating from William Bengen's 1994 research in the US, is the 4% safe withdrawal rate: you can withdraw 4% of your retirement corpus in the first year, then inflation-adjust that amount annually, and the corpus will last 30+ years through most market conditions. The flip side is the 25x rule: your retirement corpus should be 25 times your first-year annual expenses.

This rule was designed for the US, with 3% long-term inflation, 5% real equity returns, 30 years of retirement, and a Social Security floor. India needs a significant adjustment. First, inflation is higher (5–6% versus 3%). Second, there is no social security floor — every rupee of retirement must come from your own corpus. Third, life expectancy in Indian metros is rising fast, and many retirees will face 30+ year retirements. Fourth, Indian debt returns (post-tax) barely beat inflation, leaving a thinner margin of safety.

Most Indian planners recommend a corpus of 30–35x annual expenses, equivalent to a 3–3.3% safe withdrawal rate. The PV of annuity formula used in this calculator is more accurate still, because it explicitly accounts for the actual retirement period (not a generic 30 years) and the real return on your debt portfolio. Read our blog post on SIP for retirement planning for a deeper discussion of the 4% rule and its India adjustment.

Pre-retirement vs post-retirement asset allocation

Your asset allocation should look very different before and after retirement. During accumulation (your 20s through your 50s), the goal is growth — equity mutual funds should form 60–80% of the portfolio, with debt funds and gold providing diversification. Market corrections are your friend during this phase, because your monthly SIP buys more units at lower prices. Time horizons of 20–35 years smooth out the volatility.

During distribution (retirement itself), the goal shifts to capital preservation and predictable income. A retirement corpus cannot afford a 30% drop in the year you need to withdraw from it. The standard advice is to keep 3–5 years of expenses in liquid funds and short-duration debt funds (the "income bucket") and the rest in a mix of equity and debt (the "growth bucket"). Each year, refill the income bucket from the growth bucket. This is essentially a Systematic Withdrawal Plan — see our SWP Calculator for how this works in detail.

A simple glide path during accumulation: 80% equity / 20% debt until 10 years before retirement, then shift 5–8% per year into debt so you reach retirement at roughly 40% equity / 60% debt. After retirement, continue the shift to 25–30% equity / 70–75% debt, holding that mix for the long term. The small equity sleeve keeps the corpus growing faster than inflation even in retirement.

Step-up SIPs and the retirement advantage

A flat SIP is a useful baseline, but it ignores the most realistic pattern of Indian savings: salaries grow 8–10% per year through a working career, and your SIP should grow with them. A step-up SIP increases the monthly amount by a fixed percentage every year — say 10%. This dramatically lowers the starting SIP for the same corpus, or dramatically increases the corpus for the same starting SIP.

For the worked example above (₹7.59 crore corpus needed, 30 years to retire, 12% return), a flat SIP requires ₹21,499 per month. Step that up by 10% annually and the starting SIP drops to roughly ₹8,500 per month — but the year-30 SIP will be over ₹1.3 lakh. The total invested is similar, but the timing shifts in your favour: you put in less when your salary is low, more when it is high. Use our Step-up SIP Calculator to model this and read our guide on step-up SIPs explained for the mechanics.

Two final points. First, every 5-year delay in starting your retirement SIP roughly doubles the required monthly amount — see our SIP Delay Cost Calculator for the numbers. Second, the corpus this calculator produces is pre-tax — redemptions from equity funds attract 12.5% LTCG above ₹1.25 lakh per year (post-July 2024 Budget), and debt fund gains are taxed at your slab rate. Plan for a 1–2 percentage point haircut on the projected corpus, or use a slightly lower expected return to bake in the tax. Read the power of compounding in SIPs for a deeper look at how time amplifies small differences in return.

Frequently asked questions about the Retirement SIP Calculator

Mutual fund investments are subject to market risks. Please consult a SEBI-registered investment adviser before investing.