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Free Investing Tools

Standalone calculators that run entirely in your browser. Nothing you type is sent anywhere or saved.

Black-Scholes Calculator and Implied Volatility Solver

Price a European call or put, solve for the volatility implied by a market premium, and read the Greeks with their units attached. Shows where the model stops being reliable instead of hiding it.

OptionsVolatility

Portfolio X-Ray

Enter your funds and weights to see your true asset mix, what the whole portfolio costs in fees, where holdings overlap, and which ones sit in the wrong account type.

PortfolioFeesTaxes

Looking for something else?

Most Summitward calculators live inside the guide that explains them, so you get the reasoning alongside the numbers. Browse the full calculator library for retirement withdrawal rates, rent versus buy, Roth conversions, RSU withholding, and more.