Retirement Withdrawal Calculator: How to Use One and What It Shows

A retirement withdrawal calculator takes a set of inputs — primarily your portfolio balance, annual withdrawal amount, expected investment return, and inflation rate — and projects how many years your savings are likely to last. Most calculators run these projections using a fixed return assumption (a simple calculation) or a Monte Carlo simulation (a probability-based model that accounts for the variability of investment returns). Monte Carlo outputs typically show results as a probability of success — for example, an 80% chance your money lasts 30 years under the given assumptions.

These tools are educational models, not guarantees. Actual investment returns, inflation, healthcare costs, and tax rates in retirement may differ significantly from your assumptions. The SEC's Investor.gov website offers free retirement planning tools that can serve as a useful starting point. The results of any calculator should inform a broader conversation with a financial planner, not replace one. You can also explore tools like our how long will my money last calculator for a complementary perspective.

Your starting portfolio balance is the foundation of any withdrawal projection. This includes all retirement savings across all accounts — 401(k)s, IRAs, Roth IRAs, taxable brokerage accounts, and any other invested assets you plan to draw from in retirement. Make sure to enter current balances, not projected future values, unless the calculator specifically prompts you to project forward to a future retirement date.

Your annual withdrawal amount — how much you plan to take out each year — is the most sensitive variable in most calculators. Even a modest increase in annual withdrawals can significantly reduce how long your portfolio lasts. Many calculators allow you to enter either a fixed dollar amount or a percentage of your portfolio. Your expected rate of return on investments is an assumption, not a guarantee — most financial planners suggest using conservative return assumptions for planning purposes. The inflation rate affects the real purchasing power of your withdrawals over time; a common assumption is 2%–3% annually, though actual inflation may vary. Understanding how to counteract the impact of inflation on your purchasing power is an important component of retirement planning.

A widely cited starting point in retirement withdrawal planning is the "4% rule," which suggests that withdrawing 4% of your portfolio in the first year of retirement — and adjusting that amount for inflation each subsequent year — may allow your savings to last approximately 30 years in many market scenarios. This guideline originated from research by financial planner William Bengen in 1994, which analyzed historical U.S. market returns to identify a "safe" initial withdrawal rate.

The 4% rule is a useful conceptual reference, but it comes with important caveats. It was developed based on historical U.S. market data, and future returns may differ. It assumes a portfolio invested primarily in equities and bonds. It does not account for variable spending patterns, one-time large expenses such as healthcare, or individual tax situations. The SEC and FINRA both caution investors that no withdrawal rule can guarantee you will not outlive your savings — and that personalized advice is more reliable than a rule of thumb. If you are also invested in dividend-paying funds, factoring in those distributions can adjust your effective withdrawal rate.

If your retirement savings are held in tax-deferred accounts — such as traditional IRAs or 401(k)s — the IRS requires you to begin taking Required Minimum Distributions (RMDs) starting at age 73 as of 2026. RMDs are calculated annually based on your account balance and a life expectancy factor from IRS tables — you cannot choose to skip them without facing a penalty. Failing to take your RMD results in a 25% excise tax on the amount you should have withdrawn.

Many retirement withdrawal calculators allow you to factor in RMDs so you can see how the mandatory distributions affect your overall withdrawal strategy. Roth IRA accounts are not subject to RMDs during the original owner's lifetime, which is one reason some retirees hold a mix of traditional and Roth accounts to manage tax flexibility in retirement. Understanding tax minimization strategies more broadly — including for rental and investment income — can also reduce your lifetime tax burden. A tax professional or financial planner can help you sequence withdrawals across account types to minimize your overall tax obligation.

When you enter your inputs and run a retirement withdrawal calculator, the output will typically show the number of years your savings are projected to last, the probability of success across multiple market scenarios, or a chart showing your projected portfolio balance over time. A result showing 90% or higher probability of success in a Monte Carlo simulation is generally considered a strong outcome by many financial planners, though definitions vary.

Use the calculator to run multiple scenarios — changing your annual withdrawal by $5,000 or $10,000, adjusting your return assumption by one percentage point up or down, or modeling an early retirement date. Seeing how sensitive the results are to these changes can help you identify the variables that matter most for your plan. Remember that these projections are based entirely on assumptions that will not match reality exactly — review and update your projections regularly, ideally at least once per year, as your actual returns, spending, and account balances become known. If you are also planning for assisted living expenses in later retirement years, build those costs into your long-term withdrawal modeling.