Defaults to the average U.S. benefit. Set to $0 for a portfolio-only figure.
Nest egg required
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From your portfolio
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per year
From Social Security
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per year
Nest egg by withdrawal rate
Monthly Income Retirement Estimate — Financial Depth
financialdepth.com/retire-on-monthly-income
The short answer
To retire on a set monthly income, size your portfolio as (annual income − other income) ÷ withdrawal rate. At a 4% rate, every $1,000/month of income you want from the portfolio needs about $300,000 saved. Social Security, a pension, or part-time work lowers that because the portfolio covers only the gap.
Nest egg for common monthly incomes
Using your chosen withdrawal rate and Social Security estimate, here is the portfolio each monthly income needs. Change the inputs above and this table updates.
| Monthly income | Per year | Portfolio needed (with SS) | Portfolio needed (no SS) |
|---|
"$0 needed" means the Social Security amount you entered already covers that income on its own.
What the withdrawal rate really decides
The withdrawal rate is the single biggest lever here. A lower rate is safer for a long retirement but demands a larger portfolio for the same income; a higher rate needs less but raises the odds of running short. The classic 4% rule is a 30-year, historically-derived starting point — many early retirees plan at 3–3.5% for a longer horizon.
Count Social Security, pensions, or annuities you can count on. Leave out uncertain income so the portfolio target has a margin.
Size the portfolio for today's income and raise withdrawals with inflation each year — the assumption baked into the 4% rule.
Keep in mind
- Taxes come out of this income. Withdrawals from a traditional 401(k) or IRA are taxable, so your spendable amount is lower than the gross figure shown.
- Social Security timing matters. Benefits start no earlier than 62 and reach the full amount near 67. Retire before then and the portfolio carries the whole income until benefits begin.
- Constant returns aren't real. This is a deterministic estimate. Sequence-of-returns risk means a poor early market can end a plan the average math says is fine — test it with portfolio longevity and the historical backtest.
Frequently asked questions
How much do I need to retire on $3,000 a month?
At a 4% withdrawal rate, $3,000/month ($36,000/year) needs about $900,000 from your portfolio alone. If the average Social Security benefit of about $2,071/month is included, the portfolio only has to cover the remaining ~$11,148/year, which needs roughly $279,000. Lower the withdrawal rate to 3.5% and the portfolio-only figure rises to about $1.03M.
How much do I need to retire on $5,000 a month?
$5,000/month is $60,000/year. At a 4% withdrawal rate that needs about $1.5 million from the portfolio alone, or about $879,000 if you also receive the average Social Security benefit. Change the withdrawal rate or your expected benefit above to see your own number.
Does this calculator include Social Security?
It can. The Social Security field defaults to about $2,071/month, the average retired-worker benefit, and the nest-egg figure subtracts that annual amount before dividing by the withdrawal rate. Set it to $0 to see the portfolio-only number, or enter your own estimate from your SSA statement. Remember benefits can't start until 62 and reach the full amount around 67, so early retirees must cover the full income from the portfolio in the first years.
Is a monthly income the same in today's dollars each year?
This calculator sizes the nest egg for the income you enter in today's dollars. In a real plan you would raise withdrawals with inflation each year, which is why the 4% rule assumes annual inflation adjustments. A constant-return estimate like this one also ignores sequence-of-returns risk — a weak first decade can force lower spending than the math suggests.
Related tools on FinancialDepth
The forward version: income and longevity from $300K to $5M.
4% rule calculator →Compare income at 3%–5% withdrawal rates.
FIRE calculator →Estimate the date you reach your number.
How long will it last? →Test depletion under different spending and returns.