Calculator Panel
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Enter your values above and click Calculate.
What This Calculator Does
This calculator maps the lifetime trajectory of your wealth, dividing the projection into an accumulation phase (savings and growth) and a decumulation phase (safe withdrawals and growth).
How to Use This Calculator
Enter starting balance, years to accumulate, monthly deposit, accumulation return rate, years to withdraw, annual withdrawal amount, and retirement return rate. 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:
- · P = Starting investment balance.
- · PMT = Annual savings contribution during accumulation.
- · r = Annualized rate of return.
- · Withdrawal = Target annual retirement income.
Practical Example
An investor has $200,000 saved, contributes $2,000 monthly for 15 years at 6.5% return, then retires and withdraws $50,000 annually (adjusted for inflation) for 25 years at a conservative 4% return:
Step-by-Step Mathematical Walkthrough:
- 1 In Year 15, the portfolio grows to $1,114,834.
- 2 Starting Year 16, contributions stop, and they withdraw $50,000 annually.
- 3 The post-retirement portfolio compounds at 4% real return while distributing income.
- 4 At the end of 25 retirement years, the terminal balance remains highly secure at $1,057,212.
Important Assumptions & Notes
- The transition from accumulation to decumulation is instant at the transition year.
- Post-retirement withdrawals are adjusted for inflation (using real growth rates).
Common Mistakes or Considerations
- Assuming the same high rate of return in retirement as in accumulation, overlooking that retirees typically shift to conservative, lower-yielding asset allocations.
- Ignoring sequence of returns risk during the transition years.
Frequently Asked Questions
Why is a dual-phase growth calculator important?
Because your financial behavior shifts completely when you retire. You go from compounding your deposits to compound-growing while distributing cash, which behaves differently.
What is the danger of high equity allocation in retirement?
While equities grow faster, a sudden market crash right after you retire (sequence of returns risk) can deplete your portfolio permanently as you sell cheap shares for income.
How do I account for inflation in this calculator?
Use real rates of return (e.g. 5.5% accumulation and 3% retirement) so all projected cash balances are displayed in today's actual purchasing power.
What is capital preservation in FIRE?
Capital preservation means keeping your real nest egg size steady over time, withdrawing only the growth, ensuring your portfolio lasts indefinitely.
Does the calculator model down years?
It uses a smoothed average annual return rate. In reality, returns will fluctuate, making a cash buffer or emergency fund essential.