Every formula you need,
explained.
Step-by-step Math Lessons from Algebra to Calculus — plus 50 free calculators with every formula shown. No signup, no cost.
Math Lessons
Plain-English explanations, worked examples, and practice problems — free for every student.
Algebra
Linear equations, functions, quadratics, factoring, exponent rules, and more.
→Statistics
Standard deviation, p-values, normal distribution, confidence intervals, probability.
→Geometry
Pythagorean theorem, area and perimeter, angles, circles, volume, coordinate geometry.
→Pre-Calculus
Logarithms, exponential growth and decay, trigonometry, sequences and series.
→Calculus
Limits, derivatives, differentiation rules, integration, fundamental theorem.
→All Math Lessons →
Every subject in one place. Free, no signup required.
→Percentages 7
Percentage Change
Calculate the % increase or decrease between two values.
→Percentage Difference
Find the % difference between any two values with no implied direction.
→Percentage Of
What is X% of Y? Find any percentage of any number instantly.
→Discount Calculator
Find the sale price and total savings from any discount percentage.
→Tip Calculator
Calculate tip amount and split any bill between any number of people.
→Sales Tax Calculator
Add tax to a price or find the original pre-tax amount from a total.
→Percentage Increase
Find the new value after any % increase, or the % increase between two values.
→Business & Marketing 7
Gross Margin
Calculate gross profit and margin % from revenue and cost of goods sold.
→Net Profit
Bottom line profit after all expenses, interest, and taxes.
→Markup Calculator
Find selling price from cost and markup %, or find your markup %.
→Break-Even Calculator
Find the sales volume needed to cover all fixed and variable costs.
→Revenue Growth Rate
Calculate MoM, YoY growth rate and compound annual growth rate (CAGR).
→EBITDA Calculator
Calculate EBITDA and EBITDA margin from net income or revenue data.
→ROAS Calculator
Return on Ad Spend — revenue per dollar of advertising, with break-even ROAS.
→Finance & Tax 8
Compound Interest
Calculate investment growth with compounding over any time period.
→Loan Payment Calculator
Monthly payment for any loan amount, interest rate, and term.
→Mortgage Calculator
Monthly payment and total interest for any home loan.
→Savings Goal Calculator
How long to reach any savings goal, or how much to save monthly.
→Debt Payoff Calculator
How long to pay off any debt and how much extra payments save.
→ROI Calculator
Return on Investment as a percentage, including annualized ROI.
→Salary to Hourly
Convert annual salary to hourly rate with monthly and biweekly breakdowns.
→Federal Tax Estimator
Estimate 2024 federal income tax using current IRS brackets.
→Statistics 4
Standard Deviation
Calculate population or sample standard deviation from any data set.
→Mean, Median & Mode
Find the average, middle value, and most frequently occurring value.
→Z-Score Calculator
How many standard deviations a value is from the mean.
→Variance Calculator
Calculate sample or population variance from any data set.
→Algebra 4
Quadratic Formula
Solve any quadratic equation ax² + bx + c = 0, with discriminant analysis.
→Slope Calculator
Find slope and the line equation from any two coordinate points.
→Square Root Calculator
Calculate square root, cube root, or any nth root of any number.
→Exponent Calculator
Any base to any power — negative, fractional, and decimal exponents.
→Geometry & Trigonometry 4
Pythagorean Theorem
Find any side of a right triangle using a² + b² = c².
→Area of a Circle
Calculate area and circumference from radius or diameter.
→Triangle Area
Area from base & height, three sides (Heron's), or two sides & angle.
→Sin, Cos & Tan
Calculate all trig ratios and inverse functions for any angle.
→Probability 2
Health & Fitness 7
BMI Calculator
Calculate Body Mass Index from height and weight.
→TDEE Calculator
Total daily calories burned based on size and activity level.
→Calorie Deficit
Daily calorie target for any rate of sustainable weight loss.
→Calories Burned
Estimate calories burned during any exercise by weight and duration.
→Body Fat % Calculator
Estimate body fat % using the US Navy tape measure method.
→Running Pace Calculator
Find pace, finish time, or distance for any run in miles or km.
→Water Intake Calculator
Daily hydration target based on body weight and activity level.
→Education 2
Conversions 4
Temperature Converter
Convert between Fahrenheit, Celsius, and Kelvin instantly.
→Length Converter
Convert between inches, feet, meters, miles, and kilometers.
→Weight Converter
Convert between lbs, kg, oz, grams, stone, and metric tons.
→Volume Converter
Convert between liters, gallons, cups, ml, fluid ounces, and more.
→Math Lessons and Calculators — Both Free, Both Explained
Formula Hub has two sections built for people who want to actually understand math. The Math Lessons section has 33 free lessons across Algebra, Statistics, Geometry, Pre-Calculus, and Calculus — each written in plain English with worked examples and practice problems. The calculator section has 50 free calculators, each showing the formula, the Excel/Sheets code, and a full explanation. Whether you are a student working through coursework or a professional who needs a quick calculation, both sections are free and require no signup.
Now with Math Lessons
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.