Tools & research · real data, computed in your browser
Retirement math that uses real history, not averages.
Every calculator here runs on actual 1928–2025 market returns and inflation — the same data behind the videos. Every tool is free. Start with the calculator, then see how much your answer really depends on when you start.
Savings Rate Calculator
Enter your income and savings rate. See your financial-independence number and how many years it takes. The lookup table from How to Retire in 15 Years, for your numbers.
Open the calculator → FreeSurvival Odds (the 4% rule)
Drag stock allocation and time horizon and watch the historical survival odds of every withdrawal rate reshape live. Click any bar to see every individual starting year.
Open the backtest → FreeVariability Report
Your plan, run through every real starting year since 1928: fastest, median and slowest years to retire, the chance of finishing within N years, and a range for every savings rate.
Run your plan →More research
New calculators and deep dives are added alongside each video. One site, every tool.
Why "real history" matters
Most calculators assume one smooth return every year. In the real stock market, only 6 of the last 98 years landed within two points of 7%. Two people who save the same share of the same income can reach financial independence 17 years apart just because of the year they started. These tools show you that range instead of hiding it.