How Much Do I Need to Save for Retirement?
See how your monthly contribution amount—from $100 to $750 per month—affects the total retirement nest egg when starting at age 30 with $5,000 in existing savings and a 7% expected annual return, retiring at age 65.
How Monthly Contributions Build Your Retirement Nest Egg
The Retirement Savings Calculator uses two components to project your future balance. First, your current savings grows by compounding monthly at your chosen annual return rate. Second, each monthly contribution earns compound interest from the month it is deposited until retirement. Both values are added together to produce the nominal projected nest egg.
Because contributions made early in your career have decades to compound, small monthly increases have a dramatically outsized effect on the final balance. The result shown is a nominal future value—it reflects the actual dollar amount projected at retirement age, not adjusted for inflation.
- r — monthly interest rate = AnnualRate / 12 / 100
- months — (RetirementAge − CurrentAge) × 12
- MonthlyContrib — fixed monthly deposit amount
Worked Example: $300/Month Over 35 Years
Parameters: Current age 30, retirement age 65, $5,000 initial savings, $300/month contribution, 7% annual return, monthly compounding.
Step 1: Your $5,000 starting balance begins compounding immediately at 7% annually (≈ 0.583% per month). Over 35 years, this alone grows to approximately $54,192.
Step 2: Each $300 monthly deposit is added at the end of the month and then earns compound interest for all remaining months. Deposits made in month 1 compound for 419 additional months; deposits in the final month earn no additional interest.
Step 3: The combined result is $597,847. You deposit $131,000 out of pocket; compound growth contributes the remaining $466,847.
Important: This is a nominal projection. The actual purchasing power of this amount at retirement will depend on the rate of inflation between now and age 65. See the inflation scenario for details.
Contribution Comparison: $100 to $750 per Month
All rows assume: current age 30, retirement age 65 (35-year horizon), $5,000 starting balance, 7% annual return, monthly compounding. Results are nominal future values.
| Monthly Contribution | Projected Nest Egg | Total Contributions | Compound Growth | Growth Share |
|---|---|---|---|---|
| $100/mo | $237,636 | $47,000 | $190,636 | 80% |
| $200/mo | $417,742 | $89,000 | $328,742 | 79% |
| $300/modefault | $597,847 | $131,000 | $466,847 | 78% |
| $500/mo | $958,058 | $215,000 | $743,058 | 78% |
| $750/mo | $1,408,322 | $320,000 | $1,088,322 | 77% |
All values are nominal (not inflation-adjusted). Results match the live Retirement Savings Calculator. Assumes monthly compounding at 7% annual return.
Key Planning Takeaways
- •Doubling contributions more than doubles the nest egg: Going from $100/month ($237,636) to $200/month ($417,742) more than doubles the balance, because larger deposits earn more compound interest over the same 35-year period.
- •Compound growth dominates over long horizons: At $300/month, compound growth ($466,847) accounts for 78% of the projected nest egg—you directly contribute only 22% of the final balance.
- •Results are estimates, not guarantees: The 7% return rate is a user-specified assumption. Actual investment returns vary each year and can be negative. This calculator does not represent personalized financial advice.
Frequently Asked Questions
What does "nominal nest egg" mean?
A nominal value is the actual dollar amount shown at face value, without adjusting for inflation. The calculator projects the number of dollars you will have at retirement age—not the equivalent purchasing power in today's money. Inflation will reduce how much those dollars can actually buy.
Does the calculator include Social Security or pension income?
No. The Retirement Savings Calculator focuses exclusively on personal savings growth from your current balance and monthly contributions. Social Security benefits, pension income, employer matches, or other income sources are not factored in.
Is 7% a realistic annual return rate?
A 7% nominal annual return is a commonly cited long-term average for diversified equity portfolios, based on historical US stock market performance. However, actual returns are not guaranteed, vary significantly year to year, and depend on the asset mix chosen. You can adjust the return rate in the calculator to test different scenarios.
Why does compound growth make up such a large share of the final balance?
Over a 35-year horizon, each dollar deposited early has decades to multiply. Because interest earns interest on itself every month, the growth accelerates significantly over long periods. This is why starting earlier—even with the same monthly amount—produces dramatically larger results.
Does a higher contribution always beat a higher return rate?
Not necessarily. At shorter time horizons, a higher contribution amount has a proportionally larger effect. Over very long horizons (30+ years), return rate differences have an exponential impact. Both levers matter, and you can compare their effects directly in the main Retirement Savings Calculator.