MoneyBasisUnderstand your result
Nest egg
Estimated savings at retirement based on the contributions and return you entered.
Withdrawal estimate
A planning amount based on the withdrawal rate you chose. The 4% rule is a historical heuristic, not a prediction.
How this calculation works
- Enter current age, retirement age, current savings, contribution amount and expected return.
- The calculator estimates the nest egg at retirement using monthly compounding.
- A withdrawal rate, often 4%, is shown as a planning heuristic — not a guarantee.
Estimated withdrawal ≈ nest egg × selected withdrawal rate / 12
Accumulation uses nominal annual returns compounded monthly. Withdrawal rate is an adjustable planning assumption, not guaranteed income. Monthly spending is entered in today’s dollars and inflated to retirement, then raised annually.
- 4% rule
- The 4% rule is a historical planning heuristic from the Trinity Study. It is a default assumption in this calculator unless you change the withdrawal rate, not a promised retirement income.
Assumptions & limitations
- Contributions continue until retirement age.
- The expected return is a user-adjustable assumption, not a predicted market result.
- The drawdown illustration uses a nominal annual return capped at 5% as a planning assumption. It is not a forecast.
- Social Security, pensions and taxes are excluded. Inflation adjusts the spending target; portfolio charts show future nominal dollars.
Educational estimates only. MoneyBasis does not provide financial, investment, tax or legal advice.
Frequently asked questions
What does the target line mean?
It shows the balance implied by your desired monthly income and selected withdrawal rate. Both remain assumptions, not guarantees.
Can I change the retirement age?
Yes. Changing retirement age changes how long you contribute before the modeled withdrawal phase.
What is the 4% rule for retirement?
The 4% rule comes from the 1998 Trinity Study. It says withdrawing 4% of a retirement portfolio in the first year, then adjusting for inflation, historically sustained many 30-year retirements with a stock/bond mix. It is a historical heuristic, not a promise.