50 free calculators for math, finance, business, and health — each with the formula shown and Excel/Sheets code. Plus step-by-step Math Lessons built for students.
Calculate the % increase or decrease between two values.
→Find the % difference between any two values with no implied direction.
→What is X% of Y? Find any percentage of any number instantly.
→Find the sale price and total savings from any discount percentage.
→Calculate tip amount and split any bill between any number of people.
→Add tax to a price or find the original pre-tax amount from a total.
→Find the new value after any % increase, or the % increase between two values.
→Calculate gross profit and margin % from revenue and cost of goods sold.
→Bottom line profit after all expenses, interest, and taxes.
→Find selling price from cost and markup %, or find your markup %.
→Find the sales volume needed to cover all fixed and variable costs.
→Calculate MoM, YoY growth rate and compound annual growth rate (CAGR).
→Calculate EBITDA and EBITDA margin from net income or revenue data.
→Return on Ad Spend — revenue per dollar of advertising, with break-even ROAS.
→Calculate investment growth with compounding over any time period.
→Monthly payment for any loan amount, interest rate, and term.
→Monthly payment and total interest for any home loan.
→How long to reach any savings goal, or how much to save monthly.
→How long to pay off any debt and how much extra payments save.
→Return on Investment as a percentage, including annualized ROI.
→Convert annual salary to hourly rate with monthly and biweekly breakdowns.
→Estimate 2024 federal income tax using current IRS brackets.
→Calculate population or sample standard deviation from any data set.
→Find the average, middle value, and most frequently occurring value.
→How many standard deviations a value is from the mean.
→Calculate sample or population variance from any data set.
→Solve any quadratic equation ax² + bx + c = 0, with discriminant analysis.
→Find slope and the line equation from any two coordinate points.
→Calculate square root, cube root, or any nth root of any number.
→Any base to any power — negative, fractional, and decimal exponents.
→Find any side of a right triangle using a² + b² = c².
→Calculate area and circumference from radius or diameter.
→Area from base & height, three sides (Heron's), or two sides & angle.
→Calculate all trig ratios and inverse functions for any angle.
→Calculate Body Mass Index from height and weight.
→Total daily calories burned based on size and activity level.
→Daily calorie target for any rate of sustainable weight loss.
→Estimate calories burned during any exercise by weight and duration.
→Estimate body fat % using the US Navy tape measure method.
→Find pace, finish time, or distance for any run in miles or km.
→Daily hydration target based on body weight and activity level.
→Convert between Fahrenheit, Celsius, and Kelvin instantly.
→Convert between inches, feet, meters, miles, and kilometers.
→Convert between lbs, kg, oz, grams, stone, and metric tons.
→Convert between liters, gallons, cups, ml, fluid ounces, and more.
→Most online calculators give you a number and nothing else. Formula Hub is built differently — every calculator shows you the formula behind the answer, the exact Excel and Google Sheets function you can copy, and a full plain-English explanation of what the result means. Whether you are a student, a business owner, or just trying to figure out a tip, every calculator on this site gives you the understanding to use the result confidently.
The Math Lessons section brings step-by-step algebra explanations built for students. Each lesson starts with a plain-English explanation, walks through fully worked examples, includes practice problems with answers you can reveal, and links out to Khan Academy, Desmos, and other trusted resources. Start with Algebra — covering order of operations, linear equations, functions, systems of equations, and inequalities.