Many people measure retirement readiness by one thing – the size of their portfolio. Some have Rs 1 crore invested, others are contributing Rs 25,000 monthly via SIPs, and many feel comfortable simply because they still have 15–20 years left. But is knowing how much you have accumulated really enough?
The most critical question in retirement planning is not how much money you have — it is whether that money will last your entire retirement. A corpus of several crore rupees can fall short for one person, while a relatively smaller one might prove sufficient for another.
According to financial planners, a true assessment of retirement readiness comes down to just three figures – your projected monthly expenses at retirement, the number of years you will need those funds to last, and the annual withdrawal amount from your corpus. These three numbers determine whether your savings will outlast your life — or your life will outlast your savings.
These are also the three factors most investors tend to underestimate. Some underestimate how much inflation will push up future expenses. Others assume retirement will last only 15–20 years. And many do not realise how directly the withdrawal rate affects how long a corpus survives.
This article examines all three — and why getting them right is the difference between a retirement plan and a retirement guess.
Why the math behind retirement has become more complex
Until a few decades ago, retirement planning was relatively straightforward. People retired at 58 or 60, and savings sufficient to cover the next 10–15 years were considered adequate. That has changed.
Thanks to better healthcare and rising life expectancy, post-retirement periods are extending significantly. Today, it is not unusual for an individual to spend 25, 30, or even more years in retirement. Alongside that, inflation continues to erode purchasing power — the expenses that comfortably sustain a household today could be far higher in 20 years. Healthcare, medication, caregiving and lifestyle costs, in particular, tend to rise sharply with age.
This is why retirement planning can no longer be treated as a simple target — accumulate X crore and you are done. It requires balancing three factors simultaneously – expenses, duration, and withdrawals.
“Retirement duration is often the most underestimated part of retirement planning. Many investors still assume retirement will last 15 to 20 years. In reality, better healthcare and longer life expectancy mean many people could spend 25, 30 or even 35 years in retirement. That difference may not seem large initially, but it can have a significant impact on the amount of money required,” Ankit Bagadia, Director – Business, BankBazaar.
Most people, he adds, focus on current expenses and near-term financial goals but rarely consider what happens if they live far longer than expected. A corpus that looks adequate on paper can fall short in the later years.
Number 1: What will your expenses be at retirement?
Retirement planning begins with a deceptively simple question: how much will you need to spend each month after you stop working?
Most people answer this by looking at their current monthly expenses and assuming they will need roughly the same amount later. This is where the biggest miscalculation happens.
If your household runs on Rs 60,000 or Rs 1 lakh a month today, maintaining that lifestyle 15–20 years from now will cost considerably more. The reason is inflation. Costs of food, utilities, travel, household needs and healthcare keep rising over time. Retirement expenses must therefore be estimated at future prices — not today’s.
“Normally, investors are not very concerned about future expenses. They simply expect some increase in expenses at the time of retirement. However, when we accurately calculate future expenses by considering the inflation rate, we realise that the actual cost is much higher than expected. Additionally, the post-retirement period usually ranges from 15 to 25 years. Investors often do not consider the impact of inflation during this period as well, which can further increase their financial requirements,” Gibin John, Senior Investment Strategist, Geojit Investments Ltd.
The example below holds all other assumptions constant, varying only the expected monthly expense at retirement.
| Retirement Questionnaire | Values | Values | Values | Values |
| Age at when you wish to retire | 55 | 55 | 55 | 55 |
| current age | 40 | 40 | 40 | 40 |
| Life Expectancy | 80 | 80 | 80 | 80 |
| Years to left | 15 | 15 | 15 | 15 |
| Retirement life | 25 | 25 | 25 | 25 |
| Inflation | 6.00% | 6.00% | 6.00% | 6.00% |
| Post retirement return | 7.00% | 7.00% | 7.00% | 7.00% |
| Expected Monthly expense on retirement in current terms | 60000 | 75000 | 85000 | 100000 |
| Retirement corpus | 38463887 | 48079859 | 54490507 | 64106479 |
(Source: Geojit Investments Ltd)
The numbers are instructive. If monthly expenses at retirement are assumed to be Rs 60,000, a corpus of approximately Rs 3.85 crore may suffice. If those expenses are Rs 1 lakh, the required corpus climbs to roughly Rs 6.41 crore. An additional Rs 40,000 per month at retirement translates into a Rs 2.5 crore difference in the corpus needed.
“The retirement corpus for individuals primarily depends on three key factors. One of these is future expenses, which encompasses essential post-retirement costs such as healthcare, medical needs, daily living expenses, and annual vacation costs,” says Bharath Rathore, Executive Director, Anand Rathi Wealth.
The first step in retirement planning, therefore, is not to chase a ‘magic’ corpus figure. It is to honestly estimate the cost of the lifestyle you intend to lead after retirement — and then apply inflation to it.
Number 2: How many years should your money last?
If future expenses are the first critical variable, the second is equally important: for how many years will your corpus need to support you?
Most people answer this question too quickly — 15 to 20 years after retirement should be enough, they assume. That assumption can unravel an entire plan.
A person retiring at 55 or 60 today may well need their corpus to last 25, 30 or more years. The longer the retirement period, the larger the corpus required. This is not a marginal difference.
“The future cost depends on the retirement date — the longer the time until retirement, the higher the impact of inflation. The total retirement corpus required depends on both the retirement duration and the level of expenses. If the retirement period is longer, the required corpus will also be higher. On the other hand, if retirement expenses are reduced, it becomes possible to sustain the entire retirement period with a smaller corpus,” says Gibin John.
The example below keeps all other assumptions fixed, varying only life expectancy.
| Retirement Questionnaire | Values | Values | Values | Values |
| Age at when you wish to retire | 55 | 55 | 55 | 55 |
| current age | 40 | 40 | 40 | 40 |
| Life Expectancy | 80 | 80 | 80 | 80 |
| Years to left | 15 | 15 | 15 | 15 |
| Retirement life | 25 | 25 | 25 | 25 |
| Inflation | 6.00% | 6.00% | 6.00% | 6.00% |
| Post retirement return | 7.00% | 7.00% | 7.00% | 7.00% |
| Expected Monthly expense on retirement in current terms | 60000 | 75000 | 85000 | 100000 |
| Retirement corpus | 38463887 | 48079859 | 54490507 | 64106479 |
(Source: Geojit Investments Ltd)
The numbers illustrate what planners call ‘longevity risk’. If a person retires at 55 and plans only to age 70, a corpus of roughly Rs 4.03 crore may be sufficient.
If that person lives to 85, the required corpus rises to approximately Rs 7.52 crore. An additional 15 years of retirement adds nearly Rs 3.5 crore to the requirement.
“The challenge is that longevity risk is easy to overlook. Most people focus on current expenses and near-term financial goals, but very few spend time thinking about what happens if they live much longer than expected. As a result, the retirement corpus may look adequate on paper but prove insufficient later in life. For instance, a corpus designed to support expenses for 20 years may come under pressure if the retiree ends up living for another decade beyond that. This becomes particularly important in later years when healthcare costs tend to rise and inflation continues to erode purchasing power,” says Ankit Bagadia, Director – Business, BankBazaar.
The biggest risk in retirement planning is not accumulating more money than you need. It is outliving the money you have.
That is why financial planners now consider potential life expectancy — not just retirement age — as a non-negotiable input. The size of the corpus is determined not only by expenses but by how many years those expenses need to be met.
Number 3: How much you withdraw each year matters as much as how much you save
Suppose you have estimated your post-retirement expenses accurately and decided your corpus needs to last 25 or 30 years. There is still a third question: how much will you withdraw from that corpus each year?
Financial planners call this the withdrawal rate — the percentage of the retirement corpus drawn down annually to cover expenses. It matters because the corpus does not simply sit idle after retirement. A portion typically remains invested and continues to generate returns. If withdrawals are too high, the corpus depletes faster than it grows. If withdrawals are calibrated, the same corpus can last significantly longer.
“For example, if someone expects to spend about Rs 12 lakh a year after retirement and follows a withdrawal rate of 4%, they would need a retirement corpus of roughly Rs 3 crore. This is a simplified illustration, but it shows how annual expenses, retirement duration and withdrawals work together in determining the size of the corpus,” says Bagadia.
A higher withdrawal rate makes the required corpus appear smaller — but at the cost of a greater risk that the funds run out before you do. Many financial planners consider a withdrawal rate in the 4–6% range to be sustainable over the long term.
“When setting up a Systematic Withdrawal Plan (SWP) for retirement goals, one must ensure the withdrawal rate is between 4% and 6% of the total corpus. Additionally, withdrawals should be made from the debt portion; an equivalent amount should be shifted from equity to debt based on the previous year’s activity, and this cycle should be repeated to maintain liquidity and stability within the portfolio,” according to Rathore.
The point he is making is that the withdrawal process itself requires a strategy — not just a number. Many retirees use a Systematic Withdrawal Plan (SWP) to ensure a steady income stream while keeping a portion of their capital invested and growing.
Viewed this way, the retirement corpus is not a static lump sum that gets spent down. It is a resource that continues to generate income while covering expenses. A disciplined withdrawal rate significantly increases the likelihood of the corpus lasting for the long term.
How the three numbers work together
Taken individually, each of these three factors — future expenses, retirement duration, and withdrawal rate — tells part of the story. Together, they determine the total corpus you actually need.
This is why two people of the same age, with similar incomes and similar investment histories, can have very different retirement requirements. One may need Rs 60,000 a month during retirement; the other may need Rs 1 lakh. One may plan to age 70; the other to 85. One may withdraw 5% annually; the other 7%. Each variable shifts the number materially.
This also explains why the headline figures often seen online — retire with Rs 5 crore, or Rs 10 crore, or Rs 15 crore — cannot be applied universally. The right corpus is the one that fits your expenses, your expected lifespan, and your withdrawal strategy. There is no other.
“No retirement calculation can predict the future with complete accuracy. The objective is not perfection but building enough financial cushion to deal with inflation, longer life expectancy and unexpected expenses along the way,” Bagadia noted.
If any one of these three factors is underestimated — expenses too low, retirement too short, withdrawal rate too high — a corpus that looks sufficient on paper can fail in practice. Conversely, investors who revisit these three numbers periodically can adjust their goals to reflect changing circumstances and improve their financial security over time.
Three questions to ask yourself right now
If you want an honest picture of where your retirement plan stands, start with these three questions.
1. What will my expenses be at retirement?
Do not answer this by looking at what you spend today. Adjust your current monthly expenses for inflation — and factor in what your post-retirement lifestyle actually looks like. Will healthcare costs be higher? Do you plan to travel? Are there dependants to consider? The more honestly you answer this, the more reliable your corpus estimate will be.
2. How long might my retirement last?
No one knows their exact lifespan. Financial planners generally advise planning for a long one. If you retire at 55 or 60, assume your savings may need to last until 85 or 90. Planning short is the more dangerous error.
3. How much will I withdraw each year?
A regular income during retirement is essential — but not at a rate that drains the corpus prematurely. When thinking about your withdrawal rate, factor in expected investment returns, inflation, and the likelihood that your expenses will change over time.
If you do not have clear answers to these three questions, your retirement plan is incomplete. Retirement preparation is also not a one-time exercise — income, expenses, health and family circumstances all shift over the years. Revisiting these three numbers periodically is as important as making the investments in the first place.
Summing up…
Many people measure retirement readiness by how large their corpus is. But Rs 5 crore can be enough for one person and insufficient for another. The difference lies in their projected expenses, the expected length of their retirement, and how much they withdraw each year.
These three numbers reveal the real picture. Understand them, review them as circumstances change, and retirement planning shifts from guesswork into a strategy you can actually rely on.
Disclaimer: The examples and calculations used in this article are illustrative in nature and are based on specific assumptions related to inflation, returns, retirement age, and life expectancy. Actual retirement corpus requirements may vary depending on an individual’s financial goals, lifestyle, health conditions, market returns, and other factors. Readers should consult a qualified financial advisor before making investment or retirement planning decisions.
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