Will my retirement savings actually last?

Two numbers, and they are not the same number. The calculator walks the balance forward one month at a time: multiply by (1 + rate / 12), then add your contribution and the employer match at the end of the month. At the example inputs that is $75,000 today plus $1,200 a month for 384 months, ending at $1,898,347.

That figure is in the dollars of the year you retire, and those dollars buy less. At 2% inflation over 32 years, prices multiply by 1.8845, so the same balance is $1,007,326 in today's money. Every figure in the second half of this page, the spending, the withdrawal, the years it lasts, is in today's money, because that is the only unit in which a spending plan means anything.

Of the $1,898,347, you put in $307,200, the 50% match added $153,600, and growth at the assumed 6% added $1,362,547 on top of the $75,000 you started with. Turn the match off and the same plan ends at $1,435,275, $463,072 lower, which is the compounded cost of leaving a match unclaimed. The accumulation half on its own, with the crediting frequency exposed, is the compound interest calculator; this page adds what happens after you stop paying in.

Retirement spending is entered in today's dollars and rises with inflation, so the portfolio is drawn at the return after inflation rather than the headline rate. That real return is (1 + rate) divided by (1 + inflation), minus one: 3.92% at the example 6% and 2%. Subtracting one from the other gets close, but it is not the same arithmetic, and over thirty years the difference is not small.

From there the answer is one comparison. A balance holds its value when what you take out is no more than what the real return adds while it sits there. At the example inputs the balance of $1,007,326 throws off $38,810 a year without ever shrinking, which is 3.85% of it, and the plan asks for $60,000, or 5.96% in the first year. 3.85% is slightly under the 3.92% real return above, and the gap is not a rounding error: you take money out twelve times a year, so part of the growth is spent before it can compound. The withdrawal is above the growth, so the balance falls, and it reaches zero at age 94, after 27.1 years of retirement.

When the withdrawal is under that sustainable rate the calculator says the money outlives the plan rather than printing a year, because in a level-return model it genuinely never runs out. That is the model being literal, not a promise. The drawdown table under the result walks the same recurrence year by year in today's dollars and stops at age 120 whether or not the money has. If the question you are really asking is how large the balance needs to be in the first place, that is the FIRE number calculator, which starts from your spending instead of your age.

Most of it. Here is the identical plan, $75,000 today plus $800 a month with a 50% match, retiring at 67 and spending $60,000 a year, run at four assumed returns and nothing else changed.

The balance column moves by $643,558 across 3 points of assumption. The last two columns move further, because the drawdown compounds the same assumption a second time: at 4% the money is gone at age 79, and at 7% it never runs out at all. Same person, same saving, same spending. The useful way to read this page is to pick the lowest return you would still act on, and plan against that row.

It cannot, honestly. A retirement benefit is computed from your 35 highest years of indexed earnings, and the Social Security Administration already holds that record. Any number this page produced from an age and a balance would be invented, so other retirement income starts at zero and stays there until you type your own figure from your own statement. Pensions go in the same box, in today's dollars.

What the page can do is tell you the size of the hole. At the example inputs the plan draws $60,000 a year from a balance that supports $38,810 indefinitely, so it is short by about $21,190 a year. Enter that as other income and the money stops running out at all. Whether Social Security covers it is a question for your statement, not for this calculator.

The retirement age this page defaults to, 67, is the statutory full retirement age for anyone who reaches early retirement age after 2021, which is everyone born in 1960 or later. It is a benefits milestone rather than a rule about when you stop working, which is why the field is editable and why the table below prices the change.

Moving the retirement age does three things at once: it changes how many contributions land, how long everything compounds, and how many years of spending the balance has to cover. The table runs the example plan at four ages, changing nothing else.

Between 62 and 70, eight more years of work, the balance in today's money moves from $788,167 to $1,159,523 and the plan goes from 18.3 years to 35.5 years. Contributions and compounding both stretch, and the retirement they have to fund gets shorter, so the effect is larger than the extra saving alone. What this page will not tell you is what those eight years are worth to you.

Sequence of returns. The model credits the same return every single month. Real markets do not, and it matters enormously when the bad years arrive: two retirements that average an identical return can end in completely different places, because a loss taken while you are also withdrawing removes shares you never get back. A level-return model is the right tool for seeing the mechanism and the wrong one for promising an outcome. Read age 94 as the answer to a clean arithmetic question, not as a date.

Taxes on withdrawals. Money coming out of a traditional 401(k) or IRA is ordinary income in the year you take it, money in a Roth generally is not, and money in a brokerage account is taxed on its gains. This page draws gross dollars from one undifferentiated balance. If most of yours is pre-tax, the spending it actually supports is lower than the figure above: Roth versus traditional computes both branches and names the rate at which they cross, and the federal income tax calculator prices what a withdrawal costs at a given income.

Social Security and healthcare. Neither is estimated here. Medicare does not begin until 65, so an early retirement carries a premium this model never charges, and long-term care is a tail risk no level withdrawal describes. Required minimum distributions can also force money out of a traditional account faster than a spending plan would.

A constant real return is a modelling convenience. So is a spending plan that is flat in real terms for 27.1 years: real retirement spending usually falls in the middle years and rises at the end. And the contribution here never changes, while a real plan is capped by the annual deferral limit and a match capped at a percent of pay, which is what the 401(k) calculator models properly.

This calculator is built to be used without a browser. Every input is a query parameter on this page, and the same parameters on the JSON twin return the complete answer as a document.

GET /tools/retirement.json?age=45&balance=180000&monthly=1000&spending=80000&otherIncome=24000

The response carries inputs after parsing and clamping, result with the balance at retirement in nominal and today's dollars, the contribution, match and growth split, the return after inflation, the withdrawal, lastsYears and depletionAge (both null when the money outlives the plan), accumulation and drawdown rows, plus sensitivity tables by assumed return and by retirement age, drivers ranked by effect with a plain sentence each, assumptions that say for every field whether you supplied it and name the source when the default came from one, sources with a URL and an as-of date for each source the tool cites, which is an empty list on the calculators whose every default is an example input rather than a published figure, warnings, a disclaimer, and in tool the canonicalUrl and jsonUrl that carry only your non-default parameters. The canonical URL is the answer's permanent address; use it when you cite the number.

Parameters, all optional, in any order:

• age (years), default 35 years.
• retireAge (years), default 67 years, from 42 U.S.C. § 416(l) (Social Security retirement age).
• balance ($), default $75,000.
• monthly ($ per month), default $800 per month.
• matchRate (%), default 50%.
• rate (%), default 6%.
• inflation (%), default 2%, from FOMC Statement on Longer-Run Goals and Monetary Policy Strategy.
• spending ($ per year), default $60,000 per year.
• otherIncome ($ per year), default $0 per year, from Social Security Administration, my Social Security retirement estimate.

Values accept plain numbers and loose human formats such as 100k, $100,000, or 6.5%. Unknown parameters are ignored, values outside a field's range are clamped and reported in warnings, and the endpoint never fails on bad input. Responses are cacheable for a day; the defaults change when their sources publish, and tool.version changes when the method does.

• FOMC Statement on Longer-Run Goals and Monetary Policy Strategy, as of 2026-01-27. The inflation default. The Committee reaffirms its judgment that inflation at the rate of 2 percent, as measured by the annual change in the price index for personal consumption expenditures, is most consistent over the longer run with its mandate. Adopted effective January 24, 2012 and reaffirmed effective January 27, 2026. Your own cost of living can run above or below it, which is why the field is editable.
• 42 U.S.C. § 416(l) (Social Security retirement age), as of 2026-08-21. The retirement-age default. Paragraph (l)(1)(E) sets retirement age at 67 years for anyone who reaches early retirement age (62) after December 31, 2021, which is everyone born in 1960 or later. It is a benefits milestone, not a rule about when you must stop working, so the field is editable.
• Social Security Administration, my Social Security retirement estimate, as of 2026-08-22. Where the other-income figure comes from. This calculator does not estimate a Social Security benefit: that takes your 35 highest indexed earning years, and SSA computes it from the earnings record it already holds. The link is SSA's own my Social Security service, which asks you to sign in and then shows the estimate built from your record. Read it there and type it into the other retirement income field.
• Medicare.gov, Get started with Medicare, as of 2026-08-22. Medicare.gov states that "Medicare is health insurance for people 65 or older who meet citizenship or residency requirements." That is the age this page names when it says an earlier retirement carries a healthcare cost the model never charges. Nothing here prices those premiums.

Two defaults are sourced and the rest are examples. Inflation defaults to the Federal Reserve's stated longer-run objective, and the retirement age defaults to the statutory full retirement age in 42 U.S.C. § 416(l). The balance, the contribution, the match and the spending are placeholders to replace with your own, and the expected return is an assumption you choose rather than a statistic anyone publishes about your money. The other two sources back sentences rather than defaults: Social Security is not estimated here at all, so the Social Security Administration link is where to read your own figure, and Medicare.gov is the authority for the age 65 named above.

Carlo is a personal finance agent. It knows your accounts, debts, and goals, so instead of an example plan at an assumed return it can see what you are actually putting away each month, what is already invested, and what the spending you are on track for would really cost. Text it the question.

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