The length of time your money will last with systematic withdrawals depends on several factors including:

• The initial amount of your investment or savings
• The fixed withdrawal amount you take regularly (monthly, quarterly, etc.)
• The expected rate of return or interest earned on the remaining balance
• The frequency of withdrawals
• Inflation rate (if considered)
• Market performance and investment growth over time

Systematic Withdrawal Plan (SWP) calculators available online can help you estimate how long your funds will last given your specific inputs. These calculators typically require:

• Your total corpus or initial investment
• Expected annual return on investment
• Monthly or periodic withdrawal amount
• Expected inflation rate (optional)
• Withdrawal frequency and tenure

They then compute how many months or years your money will sustain these withdrawals before being depleted, factoring in the interest earned on the remaining balance after each withdrawal

. For example, if you invest a lump sum and withdraw a fixed monthly amount, the remaining balance continues to earn interest, which can extend the longevity of your funds. Conversely, higher withdrawal amounts or lower returns will shorten the duration your money lasts

. A common rule of thumb for retirement withdrawals is the "4% rule," which suggests withdrawing 4% of your initial savings in the first year and adjusting that amount for inflation annually. This approach aims to make your money last about 30 years, assuming a balanced investment portfolio

. In summary, to know exactly how long your money will last with systematic withdrawals, you should use an SWP calculator with your specific financial details. This will help you plan withdrawals sustainably and adjust your strategy if needed to ensure your funds last as long as you require