160 calculators across payroll, finance, health, construction, and more. Free to use with no sign-up or paywall.
160 free tools across eight categories, with methods and assumptions explained where they matter.
Individual paycheck calculators cover 48 US states plus Washington, DC, and show estimated federal, state, FICA, and selected local deductions using the assumptions identified on each page. Alabama and Louisiana are not yet available. Calculators support common pay frequencies, filing choices, and pre-tax deductions, but they do not replace an employer payroll system or tax advice.
Finance tools cover retirement planning with the Coast FIRE and FERS calculators, real estate analysis with cap rate and IRR calculators, and debt payoff with the debt snowball planner. The mortgage and refinance calculator compares monthly payments across loan terms. Each tool is built for personal finance decisions, not institutional models, so inputs match what a typical household actually knows.
Health calculators use published clinical formulas from the ADA, WHO, and CDC. The A1C calculator converts average blood glucose to estimated A1C and back. The period calculator predicts next cycle dates based on your cycle history. VO2 max uses the Rockport and Cooper protocol equations. Body fat, FFMI, and calorie calculators follow standard exercise science references, not proprietary black-box models.
Construction tools calculate material quantities for real projects. The square footage calculator handles complex room layouts with multiple shapes. The concrete bag calculator converts project dimensions to bag count by mix type. Asphalt, drywall, roofing, and flooring calculators output in the units contractors and homeowners actually use, including square yards, linear feet, and bag counts at standard coverage rates.
GPA calculators support both weighted and unweighted high school scales and semester cumulative averaging. Standardized test calculators convert raw scores to scaled scores and percentiles for the SAT, ACT, LSAT, and AP exams using the official conversion tables published by College Board and LSAC. The semester grade calculator determines what you need on a final exam to hit a target course grade.
Math tools include the matrix determinant calculator for 2x2 through 5x5 matrices, the antiderivative calculator with step-by-step results, and the Pearson correlation coefficient calculator for datasets up to 30 pairs. The midpoint, acceleration, and mean-median-mode calculators are built for students and professionals who need a quick, reliable result without importing a full CAS system or statistical package.
48 US states plus Washington, DC. Select a location to see an estimated take-home-pay breakdown and the assumptions used.
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