Enter your corpus, monthly withdrawal, and expected return. See whether your money outlasts you or runs out first — and by how much.
The question every retiree needs answered is not how much they have saved. It is whether what they have saved is enough to last. This SWP calculator runs that calculation: enter your corpus, the monthly amount you want to withdraw, and what return you expect the remaining corpus to earn. The output tells you whether the corpus grows, holds steady, or depletes — and if it depletes, exactly when it runs out. The year-by-year chart makes the trajectory visible rather than abstract.
At the start of each month, your corpus earns a return at the rate you set. The fund then redeems enough units to cover your withdrawal amount and credits the cash to your bank account. The remaining corpus, now slightly smaller by the number of units redeemed, earns returns again the following month. If the return earned each month is larger than the amount withdrawn, the corpus grows. If the withdrawal exceeds the monthly return, the corpus shrinks by the difference. On a Rs.1 crore corpus at 8% annual return, the monthly return is roughly Rs.66,667. A Rs.50,000 monthly withdrawal means the corpus grows by Rs.16,667 per month. A Rs.80,000 withdrawal means the corpus shrinks by Rs.13,333 per month. The sustainable withdrawal rate is the one where the corpus lasts as long as you need it to.
Three things this calculator tells you that most retirement planning conversations miss:
Each month runs the same two-step calculation. The corpus earns a monthly return equal to the annual rate divided by 12. The withdrawal amount is then deducted from that total. What remains is the new corpus balance going into the following month. This repeats 240 times for a 20-year SWP.
A concrete example shows why the math matters. Rs.50 lakh corpus, Rs.30,000 monthly withdrawal, 8% annual return. Month 1: corpus earns Rs.33,333 in return (Rs.50 lakh x 8% / 12). After the Rs.30,000 withdrawal, the corpus grows to Rs.50,03,333. The corpus is expanding because the monthly return exceeds the withdrawal. Now change the withdrawal to Rs.40,000. Month 1: corpus earns Rs.33,333 but Rs.40,000 leaves. The corpus shrinks to Rs.49,93,333. Run this forward 20 years and the difference between Rs.30,000 and Rs.40,000 per month means the difference between a growing corpus and one that is exhausted by year 14.
The calculator assumes a steady monthly return equal to the annual rate divided by 12. Actual mutual fund returns are not this smooth. A year of 15% returns followed by a year of negative 10% produces a different corpus trajectory than two consecutive years of 2.5% each, even though the averages are similar. This sequence-of-returns risk is real and it is the primary reason conservative withdrawal rates of 3 to 4% annually are the standard recommendation rather than higher rates that work only in smooth-return scenarios.
SWP is an instruction to your mutual fund: send me Rs.X every month by redeeming enough units to cover it. The rest of the corpus stays invested and keeps earning returns. The key distinction from simply withdrawing lump sums as needed is discipline and tax efficiency. Every SWP redemption creates a capital gains event on the units redeemed, not on the full withdrawal amount. On a Rs.50,000 monthly withdrawal where the capital gain component is Rs.8,000, only Rs.8,000 is taxable, not Rs.50,000. The equivalent FD interest income of Rs.50,000 is fully taxable. That difference compounds across 20 years of monthly withdrawals into a substantial tax saving.
For most retirees deploying more than Rs.15 to 20 lakh, SWP from a debt or hybrid mutual fund beats an FD on both return and tax. A senior citizen FD at 7.5% generates Rs.62,500 per month on Rs.1 crore. SWP from a debt fund earning 8% on the same Rs.1 crore generates Rs.66,667 per month before tax. The tax treatment makes the gap larger: FD interest is fully taxable as income, while SWP taxation applies only to the capital gain component of each redemption. On a Rs.1 crore corpus with a cost of Rs.60 lakh, the capital gain on each Rs.66,667 withdrawal is roughly Rs.26,667, not Rs.66,667. At the 20% tax bracket, SWP after-tax income is meaningfully higher than the equivalent FD. The case against SWP: FDs are simpler, covered under DICGC insurance, and immune to NAV volatility. For first-time retirees uncomfortable with mutual funds, a combination of 40 to 50% FD for stability and 50 to 60% debt fund SWP for tax efficiency is a practical starting point.
The 4% rule originated from US stock market research by William Bengen in 1994 and was designed for a 30-year retirement with a 50% equity portfolio. In India, applying it to debt funds earning 7 to 8% produces a different result. At 8% annual return on Rs.1 crore, the monthly return is Rs.66,667. A 4% annual withdrawal rate means Rs.4 lakh per year or Rs.33,333 per month, which is safely below the monthly return. The corpus grows permanently. A 5% rate means Rs.41,667 per month, still sustainable at 8% return. A 7% rate means Rs.58,333 per month: the corpus slowly depletes. The practical rule for Indian retirees using debt funds: keep the annual withdrawal below the expected annual return rate and the corpus is theoretically self-sustaining. Keep it 1 to 2% below the return rate and you also offset inflation.
Each SWP redemption is treated as a partial sale of mutual fund units for tax purposes. The fund redeems the oldest units first under FIFO. The gain on each unit redeemed is calculated as the redemption NAV minus the purchase NAV of that specific unit. For equity funds, gains on units held over 12 months are LTCG taxed at 12.5% above Rs.1.25 lakh annual exemption. Under 12 months is STCG at 20%. For debt funds, gains are added to your income and taxed at your applicable slab rate regardless of holding period. The practical implication: on a Rs.50,000 monthly SWP from a debt fund where the corpus was originally invested at a lower NAV, a portion of each Rs.50,000 is return of principal (not taxable) and a portion is capital gain (taxable at slab rate). If the capital gain portion is Rs.10,000 per month and you are in the 20% bracket, the monthly tax liability is Rs.2,000, not Rs.10,000.
Modifying, pausing, or stopping a SWP is completely unrestricted. Most AMC apps and platforms including Zerodha Coin, Groww, and Kuvera allow you to change the monthly amount, switch to quarterly withdrawals, pause entirely for a specific period, or stop permanently from within the app. Changes typically take effect from the next withdrawal date. The flexibility matters in practice: many retirees reduce withdrawals after the first few years when they have a clearer picture of actual expenses, or pause during months when other income is higher. This adjustability is something NPS annuities and insurance pension products do not offer.
For retirees who need the income to be predictable and the corpus to be relatively stable, debt funds are the right vehicle. Short-duration, corporate bond, and banking and PSU debt funds have historically delivered 6.5 to 7.5% with limited year-to-year variation. Balanced advantage or dynamic asset allocation funds are appropriate for retirees who have a 10-plus year horizon and some tolerance for quarterly corpus fluctuations. Equity funds work for retirees who have a second income source (pension, rental income) that covers essential expenses, allowing the SWP corpus to absorb the equity market's volatility. The approach that works for most retirees: keep 3 to 4 years of monthly withdrawal needs in a liquid or ultra-short duration fund from which the SWP runs, and park the remainder in a mix of short-duration debt and balanced advantage funds that replenish the liquid bucket annually.
When the corpus balance falls below one month's withdrawal amount, the fund house stops the SWP automatically and credits the residual balance to the bank account. The SWP does not leave you with nothing mid-month: the final payment is whatever is left. Preventing this outcome entirely requires one of three things: a lower monthly withdrawal, a higher corpus return, or a smaller starting withdrawal with planned annual increases. The monitoring discipline matters too. A quarterly review of the corpus balance against the projected balance from the calculator tells you whether the actual return is tracking the assumption. If the corpus is declining faster than the projection, the withdrawal needs to come down before the shortfall becomes irreversible.
Running SWP and SIP simultaneously is entirely possible, it is one of the standard strategies for retirees who have both a retirement corpus and ongoing part-time or consulting income. The pattern: SWP from a debt fund covers fixed monthly expenses. A small SIP in an equity index fund runs from consulting or rental income to keep building a growth corpus. The two instruments do not interfere with each other and serve distinct purposes. The more sophisticated version uses a three-bucket structure: liquid fund for 12 to 18 months of expenses with SWP running, a debt fund replenishing the liquid bucket quarterly, and an equity fund providing long-term growth that the debt fund draws from annually. The SIP adds to the equity fund to extend the corpus lifespan.
Fixed amount SWP takes a consistent rupee sum every month regardless of what the corpus is doing. On a Rs.1 crore corpus with Rs.50,000 monthly withdrawal, the fund redeems units worth Rs.50,000 every month. If NAV is high, fewer units are redeemed. If NAV is low, more units are redeemed. The principal depletes over time unless returns consistently exceed the withdrawal. Appreciation-only SWP, sometimes called growth SWP, withdraws only the returns earned above the original investment value. If the corpus was Rs.1 crore and has grown to Rs.1.08 crore, an appreciation SWP withdraws Rs.8 lakh for the year or Rs.66,667 per month. The principal stays at Rs.1 crore. The drawback: withdrawal amounts vary with market performance. In a bad year, the corpus shrinks below the original investment and there is nothing to withdraw. Most retirees with predictable fixed expenses need fixed amount SWP. Appreciation-only is better for those who have other income to cover fixed costs and want the corpus preserved for heirs.
At a 4% annual withdrawal rate, Rs.50,000 per month is Rs.6 lakh per year, which requires a corpus of Rs.1.5 crore. At 3% (conservative, corpus grows over time), you need Rs.2 crore. At 5%, which is still sustainable if the fund earns 7 to 8%, you need Rs.1.2 crore. The calculation shifts with the return assumption. If the corpus earns only 6%, the 5% withdrawal rate starts depleting it. If it earns 9%, a 5.5% withdrawal rate is sustainable. The Rs.50,000 monthly target is achievable from a corpus of Rs.75 lakh to Rs.1 crore if the portfolio is allocated to instruments earning 8 to 9% annually and withdrawals are indexed to inflation rather than kept flat.
Starting SWP on day one of retirement is the most common mistake. Most people receive retirement proceeds: PF balance, gratuity, pension commutation. Deploying everything into SWP immediately misses two years of compounding. A Rs.1 crore corpus invested in a balanced advantage fund at 9% annual return for 2 years grows to Rs.1.19 crore before the first withdrawal. That Rs.19 lakh of extra corpus means a higher sustainable withdrawal rate or a longer corpus lifespan. The practical approach: at retirement, park 18 to 24 months of expenses in a liquid fund. Start SWP from that liquid fund to cover immediate needs. Let the main corpus compound in a mix of debt and equity for 2 to 3 years. When the liquid fund approaches depletion, redirect the first quarterly withdrawal from the main corpus to replenish it. This bucket approach also protects against sequence-of-returns risk in the first years of retirement when a market downturn immediately after starting SWP is the most damaging scenario.
