Math: Calculators and Tools
Percentages, proportions and equations explained step by step.
Everyday math tends to get stuck in three places: working out a percentage without a calculator, setting up a proportion, and facing an equation that looked simple in the classroom. The tools in this category were designed for exactly those moments.
In each one, you enter the values, get the result and see the calculation laid out in steps. If the result is not what you expected, the step-by-step shows where the idea slipped. Below each calculator there is a full text about the formula, where it comes from and the most common mistakes.
Percentage Calculator
Part of a value, discount, increase and percent change, with the math shown step by step.
Open tool →Rule of Three Calculator
Simple rule of three, direct or inverse, with the proportion set up and explained.
Open tool →Fraction Calculator
Add, subtract, multiply, divide, compare and simplify fractions, with mixed numbers and decimals.
Open tool →Scientific Calculator
Expressions with parentheses, powers, roots, logarithms, trigonometry and factorials, with an on-screen keypad.
Open tool →Quadratic Equation Calculator
Quadratic formula with delta, roots, vertex and step-by-step work, even when there are no real roots.
Open tool →Where to start. If you are studying for a test, start with the quadratic equation and the rule of three: they come up in exam questions more than anything else. If you just want to solve a practical question, such as a discount at a store or an increase in a price, the percentage calculator does it in seconds.
Explore other categories
Geometry
Areas, volumes and the Pythagorean theorem with figures and examples.
Explore →Physics
Motion and electricity with the basic formulas well explained.
Explore →Conversions
Units of measurement and number bases, from kilometers to binary.
Explore →Daily Life
Dates, deadlines, age and averages for everyday calculations.
Explore →Utilities
Word counter and secure password generator, right in your browser.
Explore →