vibe_carlo — Monte Carlo Financial Planner

Portfolio

Runs entirely in your browser

Cash ($)

Market / Stocks ($)

Bonds ($)

Annual Cash Flows (real dollars)

Earnings ($)

Post-tax income from all sources (salary, Social Security, pension, etc.)

Spending / Withdrawals ($)

Low ($)

High ($)

Low ($)

High ($)

Mean ($)

Std Dev ($)

Tax Settings (optional)

Assumed tax rate on withdrawals (%)

Portfolio withdrawals are grossed up so the amount you spend is after tax. Roughly:

0% — Roth accounts, or if you're already thinking in after-tax dollars.
15–25% — Traditional 401(k)/IRA withdrawals for most retirees.
10–15% — Taxable brokerage, if most of the withdrawal is long-term capital gains.

This is a simplification. A future version will let you split the portfolio by account type.

Simulation

Years to simulate

Safe Spending

Target net worth at the end ($)

Leave at $0 to ask only that the money lasts. Raise it to also leave an inheritance or a cushion. Running the simulation also builds a table of the most you could spend at each success rate.