Find out whether your savings will actually last through retirement. This calculator runs 1,000 simulations of your plan against 98 years of real market history and gives you a probability, not just one optimistic projection.
A single average return can hide the risk that a bad market stretch early in retirement empties your portfolio. Enter your age, savings, and retirement date, then add events like Social Security or healthcare costs. Build what-if scenarios to compare choices side by side, such as retiring earlier or saving more, and get a shareable link to save or send your plan.
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Instead of projecting a single average market return (which ignores volatility and sequencing risk), our simulator stress-tests your retirement plan against real-world volatility by running 1,000 independent trials using historical market returns.
All returns are real. Projections are presented in today's dollars (purchasing power is held constant). The historical returns are adjusted annually for inflation using the Consumer Price Index (CPI), removing the need to guess future inflation rates.
The simulator samples directly from 98 years of real US market data (1928 – 2025). Equities are modeled using the S&P 500 total returns (including reinvested dividends), and fixed income is modeled using 10-Year US Treasury Bond returns. Stock and bond returns are always drawn from the same historical period, preserving how the two asset classes actually moved together.
To simulate consecutive years, the engine uses block bootstrap sampling with a 5-year block size. By copying sequential 5-year periods from history rather than single years, the simulation preserves realistic multi-year economic cycles, market momentum, and stock-bond correlations.
Out of the 1,000 randomized simulation runs, the success rate is the percentage of runs where your portfolio did not run out of money. The median represents the middle-of-the-road outcome (50% of runs did better, 50% did worse), while the 10th percentile simulates a poor market sequence (90% of outcomes were better) to stress-test your plan conservatively.
What this model does not include: taxes, investment fees, and expense ratios are not simulated, so treat the output as a pre-tax, pre-fee estimate. Results are illustrative and are not financial advice.
A Monte Carlo retirement simulation runs thousands of randomized market scenarios to estimate the probability that your portfolio will last through retirement. Instead of applying one average return to every year, it produces a range of outcomes and a success rate, the percentage of simulated paths in which you never run out of money. This calculator runs 1,000 paths built from real historical market sequences.
Most planners treat 80% to 90% as a reasonable target, and many consider anything above 95% a sign you may be saving more than you need to or retiring later than necessary. A success rate below about 70% generally means the plan needs a change: retiring later, spending less, or saving more. Because the simulation ignores your ability to adjust spending mid-retirement, a moderate success rate is less fragile in practice than it looks on screen.
The 4% rule is a single fixed guideline: withdraw 4% of your starting portfolio each year, adjusted for inflation. It compresses decades of market history into one number and assumes your spending never changes. This simulator instead models your specific plan year by year, including your contributions, retirement age, Social Security start date, and changing asset allocation, against 1,000 different market sequences, so you see a probability distribution rather than a single pass-or-fail rule of thumb.
No. The Klaris retirement scenario calculator is completely free and requires no account, email address, or sign-up. You can run a full Monte Carlo simulation, add custom life events, compare multiple what-if scenarios, and generate a shareable link without registering. Your inputs are encoded in the page URL rather than stored in an account.
At minimum: your current age, target retirement age, life expectancy, current portfolio value, and annual contributions. Optionally you can add income events such as Social Security or a pension, spending events such as pre-Medicare healthcare or travel, a stock-to-bond glide path, and what-if scenario overrides to compare different retirement paths side by side.
A what-if scenario is an alternative version of your plan compared against your baseline. For example, you can model retiring three years earlier, increasing contributions by $10,000 per year, adding part-time income, or shifting to a more conservative allocation, then see side by side how each choice changes your success rate and projected ending wealth.
Inflation, yes: every return in the underlying dataset is already adjusted for inflation using the Consumer Price Index, so all results are shown in today’s dollars and you never have to guess a future inflation rate. Taxes, no: the model does not simulate income tax, capital gains tax, investment fees, or fund expense ratios, so results should be read as pre-tax and pre-fee estimates.
Click the "Copy Shareable Link" button. Your entire plan, including ages, portfolio value, contributions, events, and scenarios, is compressed into the link itself, so anyone who opens it sees exactly the same inputs and the simulation re-runs automatically. No sign-in is required to open a shared link. Bookmarking that link is also the simplest way to save your work.
This simulator works from numbers you type in. Klaris connects your real accounts, keeps your balances and holdings current every day, and re-runs forecasts like this one against your actual portfolio, so your retirement outlook updates itself instead of going stale the moment you close the tab.