Retirement nest egg calculator
Project the retirement balance you are on track for, what it is worth in today's money, and the monthly income a 4% withdrawal rate could support.
Constant returns; 4% rule income is pre-tax and not a guarantee.
How this calculator works
This projection compounds your current savings and monthly contributions at a constant annual return until your retirement age. It is the same maths as the compound interest calculator, with a retirement framing. The “in today's money” line divides the nominal balance by cumulative inflation, which is the number to compare with today's prices when judging whether the nest egg feels adequate.
The income estimate applies the 4% rule: withdraw 4% of the balance in the first year, then increase that amount with inflation each year. It is a planning heuristic from US historical returns, not a guarantee, and it assumes a diversified portfolio and a 25–30 year retirement. If you plan a longer retirement or want more certainty, use 3–3.5% instead.
The formula
With r = return ÷ 12 ÷ 100, n = (retirement age − current age) × 12:
balance = P · (1 + r)^n + C · ((1 + r)^n − 1) / r
real value = balance / (1 + inflation)^years
safe monthly income ≈ balance × 0.04 / 12Contributions total P + C × n; everything above that is investment growth.
Worked example
From age 30 to 65, starting at 30,000 and adding 500 a month at 7% produces $1,245,712 by retirement. Adjusted for 2.50% inflation that is about $524,907 in today's money, supporting roughly $4,152 a month under the 4% rule.
Common mistakes
- Forgetting employer contributions. A 401(k) match can add thousands a year. Add it to the monthly contribution, or use the dedicated 401(k) calculator.
- Using nominal numbers to judge adequacy. A million dollars in 40 years is not a million dollars today. Always check the inflation-adjusted line.
- Retiring with no cash buffer. The 4% rule assumes you can sell assets in a downturn without touching the core portfolio. Real retirements need 1–2 years of spending in cash to avoid selling at the bottom.
Frequently asked questions
How much do I need to retire?
A rough target is 25 times your annual spending, which is the inverse of the 4% rule. If you want to spend $60,000 a year, the target is about $1.5 million in today's money; Social Security or a pension reduces the amount the portfolio must cover.
What return should I assume before retirement?
Long-run diversified portfolios have historically returned around 6–8% nominal, but the next decades may differ. Planning with 5–6% nominal is conservative and reduces the chance of a shortfall.
Does this include taxes?
No. Traditional 401(k) and IRA withdrawals are taxed as income, so the sustainable income figure here is pre-tax. Tax-advantaged accounts such as a Roth IRA behave differently.
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