Numarly

Reverse SIP Calculator

Estimate how long your investment corpus can provide monthly income.

What is it?

Reverse SIP (also called a Systematic Withdrawal Plan, or SWP) is the opposite of a SIP — instead of investing monthly, you withdraw a fixed amount every month from an existing corpus. It's commonly used to generate regular income during retirement.

Formula

Each month, the remaining corpus earns returns and then the withdrawal is subtracted, repeated until the balance runs out:

Balance(month) = Balance(month − 1) × (1 + r) − Withdrawal

Formula Explanation

The calculator simulates your corpus month by month: it grows at the expected monthly rate, then the withdrawal is subtracted. As long as the growth exceeds the withdrawal, the corpus could theoretically last indefinitely; when withdrawals exceed growth, the balance steadily declines until it's depleted.

Example Calculation

A $5,000,000 corpus with $50,000/month withdrawals at 8% return lasts roughly 13.8 years before depleting.

How to Use

  1. Enter your total investment corpus.
  2. Enter the monthly withdrawal amount you need.
  3. Enter the expected annual return on the remaining corpus.
  4. View how many months or years the corpus is projected to last.

Benefits

  • Shows whether your planned withdrawal rate is sustainable for your corpus.
  • Useful for retirement income planning without depleting savings too early.
  • Helps compare different withdrawal amounts against the same corpus.

Use Cases

  • Planning a sustainable monthly retirement income from savings.
  • Checking whether a target corpus can support a desired lifestyle.
  • Comparing different withdrawal rates to extend how long funds last.

What Your Result Means

The duration shown is how long your corpus is projected to sustain the given monthly withdrawal at the assumed return rate. If withdrawals are lower than what the corpus earns on average, funds could last far longer than the calculator's 1000-month cap suggests.

Tips

  • A withdrawal rate around 4% of the corpus annually is a commonly cited sustainable benchmark (see the Financial Freedom calculator).
  • Consider a lower withdrawal rate than the maximum sustainable one to leave a buffer for market downturns.
  • Revisit your withdrawal plan periodically as your corpus and expenses change.

Common Mistakes

  • Withdrawing more than the corpus's expected returns can sustain, depleting it faster than expected.
  • Not accounting for inflation, which erodes the real value of a fixed monthly withdrawal over time.
  • Assuming a constant return rate rather than the year-to-year variability of real markets.

FAQs

What happens if my withdrawal rate is too high?

If withdrawals exceed what the returns can sustain, the corpus depletes faster — reduce the monthly withdrawal or increase the corpus to extend the timeline.

Is this the same as a Systematic Withdrawal Plan (SWP)?

Yes, Reverse SIP and SWP describe the same strategy: withdrawing a fixed amount periodically from an invested corpus.

Does the corpus keep earning returns while I withdraw?

Yes, the remaining balance continues to earn the expected return each month, which helps the corpus last longer than a simple division would suggest.

Should my monthly withdrawal increase with inflation?

Many retirees increase withdrawals annually to keep pace with rising costs — this calculator uses a fixed withdrawal amount, so factor in a margin if you plan to increase it over time.

This calculator provides estimates based on the expected return you enter. Actual investment returns vary with market performance.

Last updated: July 25, 2026