SWP for Retirement — Building Your Monthly Income Stream

To use an SWP as a monthly pension, start from your expenses, not from your corpus: subtract the income you will receive from other sources, and the gap is the amount the SWP must pay, raised every year as costs rise. Then test whether your corpus can fund that rising gap for the number of years you need. This post walks through that build with one household and one set of stated assumptions. The assumptions are illustrations, not forecasts, and past performance does not guarantee future results.

Step 1: find the monthly gap

Take a household that expects to spend Rs. 60,000 a month in retirement and to receive a pension of Rs. 15,000 a month. The gap is Rs. 45,000 a month, or Rs. 5,40,000 a year. With a corpus of Rs. 1,50,00,000 that is a starting withdrawal rate of 3.6% a year (5,40,000 divided by 1,50,00,000). Be honest about the expenses: include insurance premiums, medical costs, taxes and an amount for the unexpected, not only groceries and utilities.

Step 2: let the withdrawal rise with costs

A flat Rs. 45,000 loses value every year. The calculator on this site holds the withdrawal fixed, so to see the effect of rising costs this post uses the calculator's own month-by-month rule and raises the withdrawal once a year. The convention: each month the balance grows by the annual return divided by 12, then the withdrawal is taken out. Months 1 to 12 pay Rs. 45,000; from month 13 the amount steps up by the stated percentage, so the monthly withdrawal in year 30 is 45,000 times (1 plus the increase) to the power 29. With zero increases the run reproduces the fixed-withdrawal result, Rs. 6,68,48,767 after 30 years for Rs. 1.5 crore at 7% and Rs. 45,000 a month. Figures are rounded to the nearest rupee, and the 7% return is an assumption applied smoothly every month.

Moving the yearly increase from 5% to 6% cuts the year-30 balance from Rs. 2,68,13,053 to Rs. 1,40,71,544 and the lifetime of the corpus from 43.6 to 34.8 years. All four cases last 30 years, but the 6% case is paying Rs. 2,43,827 a month by then, so the remaining balance covers only about five more years. The point is not that 6% is the right inflation figure. It is that a one-percentage-point change in an assumption you cannot know changes the outcome a lot. Use a range, and re-run the plan with actual cost increases as the years pass.

Step 3: watch the rate you are really drawing

The 3.6% in Step 1 is only the first-year rate. Because the withdrawal rises faster than the balance, the share of the balance you draw each year climbs. The table follows the 5% case at 7% (the same row as above), measuring the withdrawal for the year against the balance at the start of that year.

So even in a plan where the balance keeps growing for decades, the draw in year 30 is more than twice the year-1 rate. Review the plan yearly against this number, not against the original 3.6%.

Step 4: check whether your other income rises too

The earlier tables assumed the gap itself rises 5% a year, which is true only if the pension rises with expenses. If the Rs. 15,000 pension stays fixed while expenses rise 5% a year, the gap is still Rs. 45,000 in year 1 but grows faster: it reaches Rs. 2,31,968 a month in year 30 (60,000 times 1.05 to the power 29, minus 15,000), against Rs. 1,85,226 when the pension is indexed. The corpus of Rs. 1.5 crore then lasts:

At 6% the fixed-pension household falls just short of a 30-year plan. Whether your pension is indexed is a fact you can look up, so check it before you rely on the more favourable column.

Step 5: check how big the corpus needs to be

Working the same arithmetic backwards gives the smallest corpus that just lasts 30 years for a Rs. 45,000 starting gap that rises 5% a year.

These are break-even amounts, with nothing left at year 30, so they leave no margin. The household's Rs. 1.5 crore clears all three in this smooth model, but at 6% the cushion is only about Rs. 15.8 lakh. If returns arrive in a bad order, or the plan has to last beyond 30 years, the margin is what protects you.

Step 6: decide where the money sits

A pension-like SWP is only as steady as the fund it draws from. The more of the corpus sits in assets that can fall sharply, the more the monthly cheque is exposed to market swings, and the more units you must sell in a bad year to pay the same rupee amount. A common approach is to split the corpus: a portion in lower-risk holdings to cover the next few years of withdrawals, and the rest in growth assets for the long term. This post cannot tell you what mix suits you and names no fund, because that depends on your age, health, other income and temperament. Compare funds on cost, the risk the fund document describes, and the scheme's own rules for withdrawals, not on last year's return.

Common mistakes

• Setting the amount before checking the gap. Many people pick a round monthly figure that feels right and never test it against their actual expenses.
• Starting at the maximum the calculator allows. If your plan only works at the optimistic return, it has no margin.
• Assuming a pension rises with inflation. Check whether your other income is fixed or indexed, as Step 4 shows.
• Judging the plan by the first-year rate. As Step 3 shows, the share of the balance you draw can more than double over the years.
• Ignoring tax. Rules on how redemption gains are taxed change, and they are not in the calculator, so look up the current rules or ask a registered adviser.
• Never reviewing. Compare the balance with the plan every year and adjust the withdrawal, rather than waiting for the shortfall to be obvious.