How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 15% of 200 is 200 times 0.15, which equals 30.

How do I solve a quadratic equation?

Use the quadratic formula: x = (-b plus or minus the square root of b2 - 4ac) divided by 2a. Enter a, b, and c values into our calculator for instant results.

What is a logarithm used for?

Logarithms are used to solve exponential equations, measure earthquake intensity, calculate decibel levels, and analyze exponential growth or decay.

Math Calculators — Free Online Tools (2026)

Solve math problems quickly and accurately with these free calculators. From basic percentage calculations to advanced quadratic equations, these tools handle the computation so you can focus on understanding the concepts.

All Calculators

Percentage Calculator — Free Online Percent Calculator

Calculate percentages easily with our free online tool. Find what percent of a number is, percentage increase, decrease, and more in one calculator.

Square Root Calculator — Free Online Tool

Calculate the square root of any positive number instantly with this free online square root calculator.

Exponent Calculator — Free Power Calculator Online

Calculate the result of raising a base to any exponent, supporting positive, negative, and fractional powers.

Logarithm Calculator — Free Log Calculator Online

Calculate logarithms for any base including common log (base 10), natural log (ln), and binary log (base 2).

Quadratic Formula Calculator — Solve ax²+bx+c=0

Solve any quadratic equation ax²+bx+c=0 using the quadratic formula, showing both roots and the discriminant.

Fraction Calculator — Add, Subtract, Multiply & Divide

Perform arithmetic on two fractions: add, subtract, multiply, or divide and get the decimal result.

How to Use These Tools Together

1
Calculate percentages, percentage changes, and percentage differences.
2
Add, subtract, multiply, and divide fractions and mixed numbers.
3
Find square roots, cube roots, and nth roots of any number.
4
Solve quadratic equations and find the roots using the quadratic formula.

Key Terms Glossary

Percentage: A number expressed as a fraction of 100, used to represent proportions and rates of change.
Exponent: A number indicating how many times a base number is multiplied by itself.
Logarithm: The inverse of exponentiation, indicating the power to which a base must be raised to produce a given number.
Quadratic Equation: A polynomial equation of the form ax2 + bx + c = 0, solvable using the quadratic formula.
Square Root: A value that, when multiplied by itself, gives the original number.
Fraction: A numerical quantity that represents part of a whole, written as a numerator over a denominator.

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