How this retirement calculator works
It runs your plan in two phases. While you work, your current savings and monthly contributions grow at your pre-retirement return. From your retirement age, you withdraw enough each year to top up your other income (such as Social Security) to your target, with that amount rising every year with inflation, while the remaining balance earns your retirement-phase return.
The savings you need at retirement is the amount that would fund exactly those withdrawals until the age you plan to, and no more. Compare it with your projected savings: if projected savings are lower, the shortfall is converted into the extra amount you would need to save each month, starting now, to close it.
The assumptions that move the answer most
Your income target and how long you plan for. Every extra year of retirement and every extra $1,000 of yearly spending adds to the savings you need. Plan to an age beyond average life expectancy: many people live well past the average, and running out of money late in life is much harder to fix than having some left over.
Returns and inflation. Small differences compound: in the example below, assuming 6% instead of 7% before retirement cuts projected savings from $1,459,164 to $1,162,936. Inflation works the other way: at 2.5% a year, prices more than double over 32 years, so an income of $46,000 in today's dollars needs about $101,000 in the first year of retirement in the example below.
Social Security. Your benefit depends on your earnings record and the age you claim. Your personal estimate is in your my Social Security account; enter it here in today's dollars, since benefits are adjusted for inflation each year.
Ways to close a shortfall
You have four levers: save more, retire later, spend less in retirement, or accept more investment risk for a higher expected return. Retiring a few years later is often the most powerful, because it adds years of saving and growth while removing years of withdrawals. Capturing a full employer 401(k) match is the cheapest extra saving available.
Revisit the plan every year or two. Small changes made early cost far less than large ones made in your 60s.
The formulas
Savings at retirement = S × (1 + r)^Y + C × ((1 + m)^(12Y) − 1) ÷ mFirst-year withdrawal W = (income target − other income) × (1 + f)^YSavings needed = W × [1 + g + g² + … + g^(N−1)], where g = (1 + f) ÷ (1 + q)Extra monthly saving = shortfall × m ÷ ((1 + m)^(12Y) − 1)- S = current savings, C = monthly contribution, Y = years until retirement
- r = return before retirement, m = monthly rate = (1 + r)^(1/12) − 1
- q = return during retirement, f = inflation, N = years in retirement
Example
- You are 35 with $50,000 saved, contribute $750 a month, and plan to retire at 67 and plan until age 90. You assume 7% returns before retirement, 5% after, and 2.5% inflation. You want $70,000 a year in today's dollars and expect $24,000 from Social Security, so savings must supply $46,000.
- Your $50,000 grows to $435,764 over 32 years and your contributions to $1,023,400, for projected savings of $1,459,164 (about $662,126 in today's dollars).
- Inflation over 32 years multiplies prices by 2.2038, so the first-year withdrawal is 46,000 × 2.2038 = $101,373.
- Funding 23 years of withdrawals that rise 2.5% a year, while the balance earns 5%, takes $1,811,606 at age 67.
- Shortfall: $352,442. Saving an extra $258.29 a month from now on would close it. Without that, savings last until about age 84.
Frequently asked questions
How much do I need to retire?
It depends on what you will spend, how long retirement lasts, your other income, and returns and inflation. This calculator works it out from those inputs: in the example, a $46,000 yearly gap after Social Security needs about $1.81 million at 67, in future dollars.
What retirement income should I aim for?
Start from what you spend now, then adjust for costs that will change: a paid-off mortgage, no more retirement saving or payroll taxes, but often higher healthcare costs. Many people use a percentage of pre-retirement income as a first guess; your own budget is a better guide.
Why use a lower return after retirement?
Retirees usually hold more bonds and cash to reduce the chance that a market drop forces them to sell stocks at low prices. That steadier mix generally has a lower expected return. If you plan to stay invested more heavily in stocks, you can enter a higher figure.
Does this include taxes?
No. All figures are pre-tax. Withdrawals from a traditional 401(k) or IRA are taxed as ordinary income, while qualified Roth withdrawals are tax-free, so a plan built mostly on pre-tax accounts needs a larger balance to deliver the same spending.
What if my savings run out before the age I plan to?
The table shows the year the balance hits zero. From then on you would rely on Social Security and any other income. To push that age later, save more, retire later or plan for a lower income.
Sources
Last reviewed for 2026. How we calculate.