Retirement Calculator – Plan Your Retirement
Calculate your retirement savings needs based on your current age, savings, contributions, and expected investment returns. This calculator projects your retirement balance and estimates retirement income using the 4% rule.
Retirement Calculator
Assumptions: Annual contributions are made at the end of each year and earn returns in subsequent years. Compounding occurs annually. No inflation adjustment or tax modeling.
How the Calculation Works
Calculation Method: This calculator uses compound interest formulas to project retirement savings.
Future Value of Current Savings: Starting Balance × (1 + Annual Return Rate)^Years
Future Value of Annual Contributions: Annual Contribution × [(1 + r)^Years − 1] / r, where contributions are assumed to occur at the end of each year and earn returns in subsequent years.
Compounding: All calculations use annual compounding at the specified return rate.
4% Rule Estimate: Projected Balance × 4% ÷ 12 = Monthly Withdrawal Estimate. This is presented as a historical reference point only, not a guarantee.
Assumptions: No inflation adjustment, no tax modeling, no Social Security or pension included. Results are in nominal dollars.
Worked Example
Fully Auditable Example:
- Current Age: 35
- Retirement Age: 65
- Years Until Retirement: 30
- Current Savings: $50,000
- Annual Contribution: $6,000 (paid at end of year)
- Expected Annual Return: 7%
Step 1 - Future Value of Starting Savings:
- $50,000 × (1.07)^30 = $50,000 × 7.612255 = $380,612.75
Step 2 - Future Value of Annual Contributions:
- $6,000 × [(1.07)^30 − 1] / 0.07
- = $6,000 × [6.612255 / 0.07]
- = $6,000 × 94.46 = $566,760
Step 3 - Total Retirement Balance:
- $380,612.75 + $566,760 = $947,373
Step 4 - Contribution & Growth Breakdown:
- Starting Savings: $50,000
- Future Contributions: $6,000 × 30 = $180,000
- Total Contributed: $230,000
- Investment Growth: $947,373 − $230,000 = $717,373
Step 5 - 4% Rule Withdrawal Estimate:
- Annual Withdrawal: $947,373 × 4% = $37,895
- Monthly Withdrawal Estimate: $37,895 ÷ 12 = $3,158
Note: This estimate assumes a 30-year retirement horizon, no inflation adjustment, no taxes, and portfolio performance similar to historical averages. Actual results depend on market conditions and individual circumstances.
How to Use This Calculator
Key Factors Affecting Your Retirement: Starting age (earlier starts compound longer), contribution amount and consistency, expected investment returns (which vary by portfolio allocation), retirement duration, taxes on withdrawals, inflation over time, healthcare costs, and whether you have other income sources like Social Security or pensions.
This Calculator Does NOT Include: Inflation adjustment, tax modeling, Social Security benefits, pensions, healthcare costs, required minimum distributions (RMDs), account-specific rules (401k vs IRA), or sequence-of-returns risk analysis.
Frequently Asked Questions
What rate of return should I use?
Historical US stock market averages approximately 10% annually, but this varies significantly by year. Conservative: 4-5% (mostly bonds or stable investments), Moderate: 6-7% (balanced portfolio), Aggressive: 8-10% (stock-heavy). Use realistic estimates appropriate for your risk tolerance, not best-case scenarios. Remember that past returns do not guarantee future results.
What is the 4% rule?
The 4% rule is a historical guideline from a 1994 academic study that analyzed 50 years of US market data. It suggests withdrawing 4% of your retirement portfolio annually (adjusted for inflation) historically had a ~95% success rate over 30-year retirements. This is NOT a guarantee for your specific situation—it depends on inflation, actual market performance, your timeline, and other factors.
Why doesn't this calculator include inflation?
This calculator shows results in nominal (today's) dollars without inflation adjustment. Real purchasing power will be lower in the future due to inflation. For long-term planning, consider that 3% average inflation means your money will have roughly 1/3 less purchasing power in 20 years. Consider using a lower assumed return rate to account for this effect.
What if my projection shows I won't have enough?
Options include: increase monthly contributions (even small increases compound significantly), work longer (each additional year adds contributions and compound growth), pursue higher returns (carefully, with appropriate risk), reduce retirement spending goals, or plan to have other income sources (Social Security, pensions, part-time work).
Should I count Social Security in my retirement plan?
This calculator does not include Social Security. It is wise to have retirement savings that work independently of Social Security, then treat Social Security as additional income. This approach provides security if benefits are reduced or delayed.
How does starting age affect retirement?
Starting earlier dramatically changes outcomes due to compound growth. Someone who starts saving at 25 and reaches $1 million will accumulate much more by 65 than someone who starts at 35 with the same contributions and returns, because the earlier money compounds for an additional 10 years.
What about taxes?
This calculator does not model taxes. Tax treatment of retirement withdrawals varies significantly based on account type (401k, IRA, Roth, taxable brokerage) and income level. Consult a tax professional regarding your specific situation. Withdrawals from traditional 401k/IRA accounts are taxable as ordinary income; Roth withdrawals are generally tax-free.
Is this a guarantee?
No. Investment returns vary significantly and are not guaranteed. Market downturns, inflation, extended retirements, major health costs, and other factors can affect actual outcomes. This calculator is for planning and educational purposes only. Consult a qualified financial advisor for personalized retirement planning.