Probability, not a promise
See the share of simulated paths where spendable savings last through your planning horizon. It is a planning signal—not a guarantee of future returns.
Retirement stress testing
Monte Carlo retirement simulator
A straight-line forecast shows one future. A Monte Carlo simulation tests your plan across hundreds of possible market paths, so you can see the range of outcomes and the likelihood that your savings last.
Possible outcomes
Illustrative balances at age 90
90th
86%
75th
70%
Median
54%
25th
35%
10th
20%
Illustrative only. Your results use your balances, contributions, spending, timing, and selected market assumptions.
What a Monte Carlo retirement simulation tells you
Markets do not rise by the same percentage every year. The order of good and bad years matters, especially once withdrawals begin. A simulator repeatedly varies those annual returns and measures how often the plan reaches the end of the selected time horizon.
Sequence risk
Compare what happens when weaker market years arrive early in retirement rather than after your portfolio has had more time to grow.
A range of outcomes
Review 10th, 25th, median, 75th, and 90th percentile balances to understand both difficult and favorable paths.
How Finnlight uses it
Advanced simulation starts with the same plan you can inspect and change: accounts, annual contributions, retirement age, spending, Social Security, life events, taxes, and home-equity choices. It then shows how uncertainty changes the result.
- Compare a fan chart with a percentile table.
- Change retirement timing or spending and run the comparison again.
- Keep home equity separate when the home is not planned for sale.
- Use the result alongside the standard projection, not in place of it.
Test your plan against more than one future
Start with the demo, then adjust the assumptions that matter to you. Finnlight is an educational planning tool and does not provide financial, tax, or legal advice.