Investing, backtested.
Index funds, retirement pots, real historical returns. What time and a rate actually do to a number.
Bitcoin Power Law Calculator
Use the power law model to analyze Bitcoin price trends and predict future valuations. Visualize historical data and projections with interactive charts.
Retirement Calculator
Calculate how big your retirement pot will be. Monthly contributions, employer match, growth, fees and inflation, with the result in today's money. US 401(k)/IRA and UK pension/ISA.
S&P 500 Historical Return Calculator
What would an investment in the S&P 500 be worth today? Backtest any amount over any span since 1928 with real total returns, CAGR, and best and worst years.
Safe Withdrawal Calculator
How much income can your retirement pot support? Apply the 4% rule (or any rate) with inflation-linked withdrawals, growth, and a balance chart showing how long the pot lasts.
Index Fund Calculator
Backtest a blend of cash, bonds, stock indexes, and bitcoin against real historical annual returns from 1928 to 2025, with lump sum and monthly contributions.
World Index Comparison Calculator
Compare world stock indices in your own currency. Backtest the S&P 500 vs Nikkei, FTSE, CAC 40 and others with real weekly history, dividends reinvested, and inflation adjustment.