What to enter
- Current age and retirement age
- Your age today and the age you expect to stop working. The gap between them is the number of years your savings can grow.
- Current retirement savings
- The total in your retirement accounts today, such as 401(k), 403(b), IRA and similar accounts.
- Monthly contribution
- What you save each month, including any employer match, which is part of what goes into your account.
- Yearly increase in contributions
- A percentage by which you raise your contribution every year, for example along with pay raises. Zero keeps it flat.
- Expected annual return before retirement
- A steady average return on your investments while you are saving.
- Assumed inflation
- The yearly rate at which prices are assumed to rise. It converts today’s dollars into future dollars and back.
- Yearly spending in retirement
- What you expect to spend each year, in today’s dollars, including taxes if you want to be conservative.
- Yearly income from Social Security or a pension
- Your own estimate, in today’s dollars. The Social Security Administration provides benefit estimates through your online account.
- Plan to have money through age
- The age through which you want the money to last. Planning to a later age is safer because lifespans are uncertain.
- Expected annual return during retirement
- The average return on the balance while you are withdrawing. It is usually lower than the earlier return because retirees typically hold more conservative investments.
How to read your results
The results have three blocks. At retirement gives the projected balance at your retirement age, how much you contributed, how much came from growth, and what the balance is worth in today’s purchasing power. The second number is the honest one to plan with, since a large future figure buys less than it seems.
The income check compares your savings with the spending you want. It computes the yearly amount you need from savings (spending minus Social Security or pension income) in today’s dollars and the same first-year amount at retirement, after inflation. It then simulates withdrawals from your retirement age to the age you chose, raising the withdrawal each year with inflation, and reports either the balance left at the end or the age at which the money runs out. A rule-of-thumb reference shows what 4% of the balance would provide in the first year, and the balance that a 4% guideline would suggest for your spending need, which is 25 times the yearly amount.
The chart traces the balance from today through retirement. It rises while you contribute and then falls as you withdraw, so you can see when and whether it reaches zero.
How the projection works
There are two phases. In the saving phase, the annual return is converted into a monthly rate and the balance is stepped forward month by month, with the contribution added at the end of each month and, if you chose an annual increase, raised by that percentage every twelve months:
In the withdrawal phase, the yearly amount you need from savings is first converted to retirement-year dollars by multiplying by (1 + inflation)years to retirement. Each month, one-twelfth of the yearly amount is withdrawn at the start of the month and the remainder earns the retirement return. The yearly amount rises with inflation every twelve months. If the balance reaches zero, the age at which it happens is reported.
The 4% reference is a rule of thumb from historical research on how much of a portfolio a retiree could withdraw in the first year, and then adjust for inflation, without running out over roughly 30 years. It is not a guarantee, and it depends on the asset mix, the time horizon and future returns. It is shown as a benchmark next to the simulation, not as a recommendation.
Worked example
Age 30, retire at 65, $20,000 saved, $500 a month, 7% return
With 35 years to grow, the balance at 65 is projected at $1,069,238, made up of $230,000 contributed and $839,238 of growth. At 2.5% inflation, that is worth $450,546 in today’s dollars.
The person wants $60,000 a year in today’s dollars and expects $24,000 from Social Security, so the need from savings is $36,000 a year, which is $85,435 in the first year of retirement. With a 5% return during retirement and planning to age 90, the savings run out around age 80.1. The 4% reference gives $42,770 in the first year, which is $18,022 in today’s dollars.
What changes the answer. Retiring at 67 instead of 65 raises the projected balance to $1,236,985. Saving $800 a month instead of $500 gives $1,582,663. Increasing contributions by 3% a year gives $1,430,317. A 5% return instead of 7% gives $664,552. And a spending target of $90,000 instead of $60,000 raises the first-year need from savings to $156,632.
Contribution limits and employer matches
Tax-advantaged accounts have annual limits. For 2026 the IRS limit on employee contributions to a 401(k) is $24,500, and the limit for an IRA is $7,500, with higher limits for workers age 50 and older through catch-up contributions. Many employers match part of what you contribute, which is effectively an immediate return on your savings, so contributing at least enough to receive the full match is a common first step. Whether to use pre-tax or Roth contributions depends on your current and expected future tax rates, and the calculator does not model taxes on contributions or withdrawals.
To see how a 401(k) contribution affects your paycheck, use the take-home pay calculator.
What the calculator does not know
A retirement plan involves several uncertainties this tool cannot resolve: how long you will live, how markets will behave, especially in the first years of retirement, what inflation will be, what your health care will cost, when you will claim Social Security and how your taxes will change. A steady return is an illustration; a poor market early in retirement can deplete savings much faster than a smooth average suggests. The calculation treats spending, Social Security and pension income as fixed real amounts and ignores taxes on withdrawals, required minimum distributions, home equity and other assets.
Treat the results as a way to compare choices, such as saving more, retiring later or spending less, rather than as a promise. For deeper planning, consider talking with a licensed financial planner. To model the growth part alone, use the investment return calculator, and to see purchasing power over time, the inflation calculator.
Frequently asked questions
How much do I need to retire?
It depends on the spending you want, other income such as Social Security, how long you plan for and how your investments perform. The calculator’s income check tests your own numbers. The 4% guideline, which implies about 25 times your yearly need from savings, is a common starting reference, not a rule.
Are the figures in today’s dollars?
The spending and income inputs are in today’s dollars. The projected balance is shown both in future dollars and in today’s purchasing power, and withdrawals rise with inflation.
What is the 4% rule?
It is a guideline from historical studies suggesting that withdrawing about 4% of a portfolio in the first year, then adjusting for inflation, has lasted about 30 years in past markets. It is not a guarantee, and it may be too high or too low for your situation.
Should I include Social Security?
If you expect to receive it, yes. Use the estimate in your Social Security account, which is in today’s dollars. Benefits depend on your earnings history and the age at which you claim.
Why does the balance jump when I retire later?
Working longer does three things at once: it adds contributions, it gives the balance more time to compound, and it shortens the time the savings must last.
Is this financial advice?
No. It is a planning estimate. A licensed advisor can review your full situation.