Paid script
Retirement Monte Carlo simulator (Python script)
See the odds your savings last instead of a single straight-line projection. Enter your age, savings, contributions and planned spending.
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Paid script
Retirement Monte Carlo Python script
Buy this script on its own for $19, one time. No membership needed. It runs on your own computer and nothing you enter leaves it. Read how it works and the questions below first.
The Personal Finance Suite includes this and 3 more tools for $29. Members get this included. See the membership or sign in. Already bought it? Email me my access link.
How it works
How it works
The script runs 10,000 simulated lives. Each draws random yearly returns from the average and volatility you set, adds your contributions until retirement, then withdraws your spending (rising with inflation) minus any Social Security-type income. Results are in today's dollars. It reports the chance the money lasts to your end age, the poor, middle and good outcomes at retirement and at the end, and the yearly spending with about a 90% chance of lasting. The inputs are your assumptions, not predictions, and taxes, fees and changing spending are not modeled.
FAQ
About this calculator
Is this a prediction of my retirement?
No. It shows how your plan behaves under assumptions you choose. Real markets, taxes, health costs and your own spending will differ.
What returns should I enter?
That is your call. The script shows how sensitive the result is, so try a few values: a lower average return and a higher volatility show how a weaker market would affect you.
Does it replace a financial planner?
No. It is a planning tool for general information, not financial, investment or tax advice.
Is anything saved?
No. The math runs in your browser and nothing you enter is sent to us.
Is this tax or financial advice?
No. It is a calculator for general information. Check the numbers against your own records, and ask an accountant before you act on them.
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General information, not tax or legal advice. How we write and check our tools.