Retirement Savings Calculator
Project retirement savings with monthly contributions and a constant-return scenario, then compare the result with a 4% first-year withdrawal planning target.
Last updated August 24, 2026
Retirement Savings Calculator
Loading calculator...
This calculator answers two separate planning questions: what could your current savings and monthly contributions grow to, and how does that scenario compare with a portfolio target based on your desired annual retirement income?
Use several return and contribution scenarios instead of treating one result as a forecast. The tool does not model Social Security, a pension, taxes, fees or inflation.
How It Works
The projection compounds current savings monthly and treats each monthly contribution as arriving at month-end. The result uses a constant annual return entered by the user.
- Projected balance = future value of current savings + future value of monthly contributions.
- Planning target = desired annual income ÷ 4%.
- First-year income illustration = projected balance × 4%.
- Additional monthly amount solves for the contribution needed to close the modeled gap by retirement age.
The 4% figure is a historical planning heuristic, not a guaranteed safe withdrawal rate for every retirement length, asset mix or market path.
Understanding Your Results
“Projected savings” separates your contributed dollars from modeled growth. “Target” is the amount implied by the desired income and 4% heuristic. A shortfall is not a recommendation to take more investment risk: test a later retirement date, a different contribution, lower spending or income from Social Security and pensions in a fuller plan.
Use a range, not one retirement forecast
Run a conservative, middle and optimistic return scenario. Then compare the monthly contribution needed in each. Inflation matters because the desired income is entered in nominal dollars; if your target is stated in today’s purchasing power, increase it over time or use a lower real-return assumption.
Assumptions Used
- Monthly compounding
- Contributions arrive at month-end
- Constant return entered by the user
- No taxes, fees, inflation, Social Security or pension income
Pros and Considerations
Benefits
- •Separates contributions from modeled growth
- •Shows the gap to an income-based target
- •Makes the return and contribution assumptions editable
Considerations
- •Uses a constant return rather than volatile markets
- •Does not include inflation, tax, fee or benefit detail
- •The 4% heuristic may not fit very long or unusual retirements
Important Notes
- •Run multiple return scenarios
- •Account limits and employer-match rules are outside this model
Warnings
- •Investment returns are not guaranteed
- •Do not interpret a 4% illustration as an approved personal withdrawal plan