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Math Calculators

Free math calculators for everyday questions, from quick checks to detailed breakdowns.

Featured calculators

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    Percentage Calculator

    Calculate percentages, increases, decreases, and differences.

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Math tools (212)

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    Ratio Calculator

    Simplify and compare ratios.

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    Ratio Percentage Calculator

    Percentage share of each part of a ratio.

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    Ratio to Decimal Calculator

    Convert a ratio a:b to a decimal.

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    Ratio to Fraction Calculator

    Convert a ratio a:b to a fraction a/b.

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    Rational or Irrational Calculator

    Whether the k-th root of a whole number is rational.

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    Reciprocal Calculator

    The multiplicative inverse of a number.

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    Rectangle Calculator

    Area, perimeter and diagonal of a rectangle.

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    Rectangular Prism Volume Calculator

    Volume of a rectangular prism (box).

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    Reference Angle Calculator

    Acute angle between the terminal side and the x-axis.

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    Regular Polygon Calculator

    Area, perimeter and angles of a regular polygon.

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    Remainder Calculator

    Quotient and remainder of a whole-number division.

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    Reverse Percentage Calculator

    Work backwards from a final amount to the original value before a percentage increase or decrease.

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All math calculators by topic (207)

Advanced

Algebra

Arithmetic

Basic

Calculus

Charts

Chemistry

Coordinates

Electrical

Fractions

Geometry

Matrices

Number Theory

Trigonometry

Vectors

Volume

About math calculators

Math Calculators help you turn a question into a clear, checkable answer. Each tool lists its inputs, shows the formula it relies on and explains how to read the result.

Browse by topic using the filters, or search for a specific tool. Tools that are still being built are clearly marked as previews and are not presented as finished calculators.

Frequently asked questions

Are the math calculators calculators free?

Yes. Every calculator on Calculator Atlas is free to use and requires no sign-up.

How are results verified?

A calculator is only published after its formula has been implemented, tested against independently computed reference values. It is an automated check, not a professional review.

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