A clean, focused suite of calculators for active investors, options traders, and expats. No bloated forms. No upsells. Just the numbers you need to make a decision.
Each tool runs entirely in your browser. Inputs never leave your device.
Long calls, puts, and verticals. Breakeven, max gain, max loss — instantly.
Open calculator →See what borrowing on margin really costs at any broker tier — daily, monthly, annual.
Open calculator →Calculate share size from account risk, entry, and stop. The 2% rule, automated.
Open calculator →Weighted-average cost across multiple lots, plus break-even after averaging down.
Open calculator →Future value with monthly contributions, any compounding frequency, and inflation adjustment.
Open calculator →Compound annual growth rate — the smoothed annual return between any two values.
Open calculator →Risk-adjusted return. Direct inputs or paste a return series — both modes supported.
Open calculator →Project compounded returns with dividend reinvestment, contributions, and growth.
Open calculator →How long until you can retire on a 4% rule? Includes savings rate sensitivity.
Open calculator →Monthly payment, total interest, and how much extra principal saves you.
Open calculator →Most "free" calculator sites are slow, full of trackers, and built by SEO farms that don't actually trade. BasisCalc is the opposite: every formula here is one I've personally used to size positions, evaluate margin costs, and plan international tax exposure.
All math runs in your browser. Your numbers never touch a server, ever.
Works on your phone during market hours. No layout breaking on small screens.
Standard finance formulas, double-checked against broker statements and IRS publications.