Retirement Calculator

This calculator uses compound interest to project your retirement savings. Enter your current age, retirement age, existing savings, and monthly contributions. The calculator applies your expected annual return rate, then adjusts the result for inflation to show real purchasing power.

The calculator runs two compound-interest formulas side by side, using a monthly rate (your annual return divided by 12) and the number of months between now and your retirement age. Your current savings grow as a lump sum: P × (1 + r)^n, where P is your current balance, r is the monthly rate, and n is the number of months.

Your monthly contributions grow as an ordinary annuity: PMT × ((1 + r)^n − 1) / r, which accounts for each contribution earning returns for a different length of time (a contribution made in year one compounds for decades, while one made the month before retirement barely compounds at all). Adding the two results together gives the total projected balance; subtracting your actual contributions from that total gives the interest earned, which is the growth attributable purely to compounding rather than to money you put in.

The monthly withdrawal figure is calculated as your projected total savings multiplied by 4%, divided by 12. This 4% figure traces back to financial planner William Bengen's 1994 research and the later Trinity Study, both of which tested historical market returns to find a withdrawal rate that a retirement portfolio could sustain for roughly 30 years without running out, even across periods that included major market downturns.

The rule is not a guarantee. It assumes a diversified stock-and-bond portfolio, a fixed inflation-adjusted withdrawal each year, and roughly a 30-year retirement horizon. More recent analysis has proposed rates ranging from about 3.3% (more conservative, accounting for lower expected future returns) up to 5% (for shorter retirement horizons). The biggest risk to any fixed withdrawal rate is sequence-of-returns risk: a market downturn in the first few years of retirement does far more damage than the same downturn happening later, because you are selling a larger share of your portfolio at depressed prices.

If you're starting late, the tax code gives older savers a way to contribute more. For 2026, workers age 50 and up can add an extra $8,000 catch-up contribution to a 401(k) on top of the $24,500 standard limit, for a total of $32,500. Workers age 60 through 63 get a higher "super catch-up" of $11,250 instead of the standard $8,000, allowing total 401(k) contributions of $35,750 during those four years under the SECURE 2.0 Act (this super catch-up replaces, rather than stacks with, the regular 50+ catch-up). IRA catch-up contributions add an extra $1,000 to the standard limit for anyone 50 or older. Front-loading contributions during these catch-up-eligible years can meaningfully close the gap this calculator projects.

When you claim Social Security also changes your retirement income, independent of personal savings. Claiming at 62, the earliest age allowed, permanently reduces your monthly benefit compared to your full retirement age (66-67 depending on birth year). Waiting past full retirement age increases your benefit by roughly 8% for every year you delay, up to age 70. This calculator models personal savings only, but your Social Security claiming age is one of the biggest levers you control over lifetime retirement income, get a personalized estimate at ssa.gov before settling on a retirement age here.