Retirement Planning
Know your retirement date.
With math, not hope.
Run 10,000 Monte Carlo simulations across eight withdrawal strategies. See your success probability, spending floor risk, and exactly when you can stop working.
14-day free trial · No credit card required
How It Works
10,000 possible futures, one clear answer
Monte Carlo simulation doesn't predict the market. It models thousands of plausible outcomes so you can plan for uncertainty instead of pretending it doesn't exist.
Step 01
Enter your assumptions
Current savings, contribution rate, expected return, inflation, retirement age. Thermal pre-fills what it can from your linked accounts.
Step 02
Run 10,000 simulations
Each simulation randomizes market returns based on historical distributions. No two runs are the same, just like real markets.
Step 03
See your probability
A portfolio success rate, a spending floor breach rate, and a clear answer: can you retire when you want to, or do you need to adjust?
Withdrawal Strategies
Eight strategies. Your retirement, your rules.
The 4% rule is a starting point, not the answer. Thermal models eight distinct withdrawal approaches so you can find the one that fits your risk tolerance and lifestyle.
Guardrails (Guyton-Klinger)
Adjusts withdrawals up or down based on portfolio performance. Spends more in good years, cuts in bad ones.
4% Rule
The classic: withdraw 4% of your initial portfolio, adjusted for inflation each year. Simple and battle-tested.
Dynamic Percentage
Withdraws a fixed percentage of the current portfolio each year. Naturally adjusts to market conditions.
Variable Percentage Withdrawal (VPW)
Calculates withdrawals based on remaining life expectancy and asset allocation. Mathematically optimized.
Floor and Ceiling
Sets minimum and maximum withdrawal bounds. Guarantees a spending floor while capturing upside.
Endowment
Models university endowment spending rules. Smooths withdrawals across market cycles.
Buy, Borrow, Die
Borrows against portfolio instead of selling. Models loan mechanics, margin rates, and stepped-up basis.
Custom
Define your own withdrawal schedule year by year. Full control for those who want it.
The Bridge
See how daily spending affects your retirement
Most apps treat budgeting and retirement as separate problems. Thermal's Bridge connects them. Cut $200 a month from dining out and watch your projected retirement date move forward in real time.
14-day free trial · No credit card required
10,000
scenarios per simulation
Ready to run your first simulation?
Link your accounts, set your assumptions, and see your retirement probability in under five minutes.
14-day free trial · No credit card required
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