Calculator Panel
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Enter your values above and click Calculate.
What This Calculator Does
This calculator helps you understand your total cash flow during retirement by combining portfolio withdrawals with guaranteed external income sources.
How to Use This Calculator
Enter your accumulated portfolio size, your target initial annual withdrawal rate, and any other monthly income from Social Security, pensions, or work, then click Calculate.
How the Calculation Works
The underlying math engine processes your inputs using exact formulas. This systematic approach ensures professional, institutional-grade calculation precision:
Mathematical Formula
Formula Legend:
- · Portfolio Value = Total accumulated nest egg size.
- · Withdrawal Rate = Annual rate at which capital is drawn from the portfolio.
- · Other Monthly Income = Non-portfolio income streams like Social Security, rental yield, or pension payouts.
Practical Example
Suppose you have a $1,000,000 portfolio, a 4% initial annual withdrawal rate, and $1,500/month in other guaranteed retirement income (Social Security/Pension):
Step-by-Step Mathematical Walkthrough:
- 1 Your portfolio generates $40,000 in annual income ($1,000,000 * 4.0%).
- 2 Dividing this annual portfolio income into months gives $3,333.33 per month.
- 3 Adding your other guaranteed monthly income of $1,500 yields a total monthly retirement income of $4,833.33.
- 4 Over a 30-year retirement, you will draw a total of $1,200,000 from your portfolio while leaving a terminal balance depending on actual market returns.
Important Assumptions & Notes
- The initial withdrawal amount is adjusted upward annually by the expected inflation rate.
- All non-portfolio income streams remain stable or increase with inflation.
Common Mistakes or Considerations
- Failing to account for taxes on traditional IRA/401(k) withdrawals, which reduces your net spendable income.
- Relying on high withdrawal rates that can quickly deplete your principal during market downturns.
Frequently Asked Questions
Is other retirement income taxable?
Social Security can be partially taxable depending on your total provisional income, while pension benefits and traditional retirement account withdrawals are generally fully taxable as ordinary income.
What happens if inflation is higher than expected?
Higher inflation means you will have to increase your portfolio withdrawals faster to maintain your purchasing power, raising the risk of depletion.
What is the sequence of returns risk?
The risk that market downturns occur early in your retirement. If you make fixed withdrawals while the market is down, you sell more shares at depressed prices, which can severely shorten how long your portfolio lasts.