Free Online Math Calculators

A hosted suite of browser math calculators, from basic arithmetic through linear algebra — add fractions, find the GCF or LCM, solve a quadratic equation, check the Pythagorean theorem, multiply or invert a matrix, and more. Every tool shows the step-by-step working, not just the answer. No installs, no sign-up, results as you type. Free on LK Forge — no sign-up.

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Arithmetic

Fractions, percentages & number basics
Free

Percentage Calculator

Answer the three common percentage questions: what is X% of Y, X is what percent of Y, and the percent increase or decrease from one number to another.

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Free

Percentage Increase Calculator

Percentage increase, decrease and change between two values — or increase a number by a percent — with the working shown.

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Free

Fraction Calculator

Add, subtract, multiply, divide and simplify fractions and mixed numbers — with the answer as a reduced fraction and a decimal, plus the working.

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Free

Mixed Number Calculator

Add, subtract, multiply and divide two mixed numbers, or convert a mixed number to an improper fraction — with the answer as a mixed number, an improper fraction and a decimal.

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Free

Ratio Calculator

Simplify a ratio to lowest terms or solve a proportion a:b = c:d for a missing value, with the working shown at every step.

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Free

Ratio to Fraction Calculator

Convert a ratio to a fraction in lowest terms — a:b becomes a/b with its decimal and percentage, and multi-part ratios give each part as a fraction of the whole.

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Free

Proportion Calculator

Solve for the missing value in a proportion (a/b = c/d) using cross-multiplication, with each step of the algebra shown.

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Free

Rounding Calculator

Round any number to the nearest place, decimal or significant figure, with half-up, banker's, ceiling, floor and truncate modes — and see which digit decided.

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Free

Long Division Calculator

Divide two numbers the long way, with the full step-by-step bring-down process and the quotient plus remainder shown.

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Free

GCF Calculator

Find the greatest common factor of two or more numbers, with every Euclidean-algorithm reduction step shown.

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Free

LCM Calculator

Find the least common multiple of two or more numbers, using the GCF relationship with every pairwise reduction step shown.

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Free

PEMDAS Calculator

Solve any expression in the correct order of operations (PEMDAS / BODMAS), one step at a time, with parentheses, exponents and roots.

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Free

Scientific Notation Calculator

Convert any number to scientific, E- and engineering notation — or add, subtract, multiply and divide in scientific notation, with the steps explained.

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Free

Significant Figures Calculator

Count the significant figures in a number and round any value to a chosen number of sig figs, with the rules applied.

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Free

Decimal to Fraction Calculator

Convert a terminating decimal to an exact fraction in lowest terms, with the mixed-number form.

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Free

Fraction to Decimal Calculator

Convert a fraction to its decimal form and find out whether it terminates or repeats.

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Free

Simplify Fractions Calculator

Reduce a fraction to lowest terms by dividing by the greatest common divisor.

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Free

Prime Factorization Calculator

Break a whole number into its prime factors, shown in exponent form.

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Free

Modulo Calculator

Remainder and modulo of a ÷ n, with the quotient and a non-negative form.

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Algebra & Calculus

Equations, functions & calculus
Free

Inequality Calculator

Solve a linear or quadratic inequality, with the solution in interval notation and on a number line.

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Free

Graphing Calculator

Plot multiple functions of x on an interactive, zoomable graph with a live coordinate readout.

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Free

Domain and Range Calculator

Find the domain and range of a function in interval notation, shown on a graph.

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Free

Vertex Calculator

Vertex, axis of symmetry, minimum or maximum and vertex form of a parabola.

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Free

Parabola Calculator

Vertex, axis of symmetry, focus, directrix and intercepts of a parabola.

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Free

Quadratic Formula Calculator

Solve any quadratic equation ax² + bx + c = 0 for real or complex roots, with the discriminant and every step of the formula shown.

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Free

Factoring Calculator

Factor a polynomial over the rationals — GCF, difference of squares, trinomials, and higher-degree via the rational-root theorem, with every step shown.

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Free

Polynomial Calculator

Add, subtract, multiply, or divide two polynomials — like terms collected, products expanded, and long division with a quotient and remainder.

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Free

System of Equations Solver

Solve a system of two linear equations with two unknowns using Cramer's rule, with the determinant and every step shown.

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Free

Word Problem Solver

Turn a linear "find the number" word problem into an equation and solve it step by step — like "10 added to four times a number is 46".

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Free

Exponent Calculator

Raise any base to any power, including negative and fractional exponents, with step-by-step working.

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Free

Square Root Calculator

Square root of any number as a decimal and, for whole numbers, in simplified radical form like 6√2.

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Free

Summation (Σ) Calculator

Evaluate a sigma-notation summation of a series in k over an index range, with the terms expanded.

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Free

Absolute Value Calculator

Absolute value of a number, or solve an absolute-value equation |ax + b| = c with the two-case working.

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Free

Synthetic Division Calculator

Divide a polynomial by a linear factor x − r using synthetic division; quotient and remainder shown.

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Free

Cube Root Calculator

Cube root of any number as a decimal and, for whole numbers, in simplified radical form.

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Free

Discriminant Calculator

Discriminant b² − 4ac of a quadratic and how many real roots it has.

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Free

Completing the Square Calculator

Rewrite a quadratic ax² + bx + c in vertex form a(x − h)² + k.

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Free

Interpolation Calculator

Linear interpolation to estimate a value between two known points.

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Free

Scientific Calculator

Trigonometry, logarithms, powers, roots, factorial, constants and memory — in degrees or radians, with full keyboard support and no sign-up.

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Free

Log Calculator

Calculate a logarithm in any base, including log base 10, natural log (ln) and log base 2, with the change-of-base formula shown.

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Free

Exponential Function Calculator

Evaluate f(x) = a·bx for any base — including ex, 2x and 10x — graph the curve, mark the point, and see growth or decay.

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Free

Factorial Calculator

Calculate n! for any non-negative integer, with the full multiplication chain shown for small numbers and fast results for large ones.

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Free

Permutation Calculator (nPr)

Count the ordered arrangements of r items chosen from n, computed exactly with the formula shown.

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Free

Combination Calculator (nCr)

Count the ways to choose r items from n when order does not matter, computed exactly with the formula shown.

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Free

Derivative Calculator

Differentiate any function of x and see f′(x) with the power, product, quotient, and chain rules shown, plus a graph of f and f′.

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Free

Integral Calculator

Integrate any function: the indefinite integral (antiderivative) with steps, or a definite integral and the area under the curve between two limits.

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Free

Partial Derivative Calculator

Partial derivative with respect to any variable and the full gradient of a multivariable function, with the rules shown.

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Free

Taylor Series Calculator

Expand a function as a Taylor or Maclaurin series to any order about any center, with each term and an approximation plot.

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Free

Complex Number Calculator

Add, subtract, multiply, divide complex numbers in rectangular, polar and exponential form, plus powers and roots.

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Free

Limit Calculator

Find the limit of a function as x approaches a value or infinity, with one-sided values, a table of approaching values, and a graph.

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Free

Arithmetic Sequence Calculator

nth term and sum of an arithmetic sequence from the first term, common difference and count.

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Free

Geometric Sequence Calculator

nth term, partial sum and infinite sum of a geometric sequence.

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Free

Binomial Coefficient Calculator

C(n, k) “n choose k” computed exactly, with the matching row of Pascal’s triangle.

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Geometry

Area, distance, angles & shapes
Free

Circle Area Calculator

Find the area, circumference, diameter or radius of a circle from any one measurement, with the formula and steps shown.

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Free

Sphere Surface Area Calculator

Find the surface area, volume, radius or diameter of a sphere from any one measurement, with the formula and steps shown.

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Free

Polygon Area Calculator

Find the area of any polygon — an irregular shape from its coordinates (shoelace formula), a triangle from three sides (Heron), or a regular polygon from its side length.

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Free

Volume Calculator

Volume of a cube, box, sphere, cylinder, cone or pyramid, with surface area and the formula shown.

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Free

Surface Area Calculator

Surface area of a cube, box, sphere, cylinder, cone or pyramid, with volume and the formula shown.

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Free

Distance Formula Calculator

Distance between two points in the plane, with the horizontal and vertical differences.

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Free

Area of a Triangle Calculator

Triangle area from base and height, three sides (Heron), or the coordinates of its vertices.

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Free

Pythagorean Theorem Calculator

Find a missing side of a right triangle from the other two, using a² + b² = c², with every step of the formula shown.

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Free

Midpoint Calculator

Find the midpoint and the distance between two coordinates, with the midpoint and distance formula steps shown.

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Free

Slope Calculator

Find the slope of a line from two points (rise over run), plus the angle of incline, the equation y = mx + b, the distance, and the midpoint.

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Free

Law of Cosines Calculator

Find a triangle side (SAS) or all three angles (SSS) with the law of cosines.

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Free

Law of Sines Calculator

Find a triangle side (AAS) or an angle (SSA) with the law of sines, including the ambiguous case.

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Matrix & Vectors

Linear algebra operations

Statistics

Averages, spread & distributions
Guide Three hard problems, one method: how to chain these calculators A worked walkthrough — solve a thrown-ball problem, an outlier check and a 3×3 linear system end to end by wiring the Quadratic Formula, Derivative, Integral, Z-Score, Determinant and Matrix Solver calculators together. Data Study Tiled vs naive matrix multiplication: what actually makes it fast We benchmarked naive, loop-reordered and tiled matrix multiply against a BLAS library — loop order alone was 6.3× faster, tiling was situational, and BLAS was 155× the naive loop. The measured numbers behind the matrix calculators here.

How These Math Calculators Work

Focused, step-by-step tools in two tiers — basic arithmetic and number basics, plus advanced algebra, geometry, and linear algebra. Every tool shows the step-by-step working. Pick a calculator, enter your values, and read the result instantly.

1

Pick a calculator

Choose the right tool for the job — Quadratic Formula and System of Equations for algebra, GCF and LCM for number theory, Pythagorean Theorem for geometry, or Fraction and PEMDAS for the basics. Each is a single page with one job.

2

Enter your values

Type numbers, coefficients or coordinates. Calculation happens live as you type — there is no submit button to wait on, and nothing is sent to a server.

3

Read the step-by-step working

See the answer broken down one step at a time — not just the final number. Everything runs in your browser, so the tools stay fast and private and keep working offline once loaded.

Frequently Asked Questions

What calculators are in the LK Forge Math suite?
Math is a free suite of browser-based step-by-step calculators hosted on LK Forge. It covers algebra (Quadratic Formula, System of Equations, Log, Proportion), number theory (GCF, LCM, Ratio, Long Division, Factorial), geometry (Pythagorean Theorem, Circle Area, Sphere Area, Midpoint) and fractions and basics (Fraction, Rounding, Percentage, PEMDAS, Scientific Notation and a general Scientific Calculator). Every calculator shows its working, not just the final answer, and every calculation runs in your browser — nothing you enter is uploaded or stored, and there is no sign-up.
Are the math calculators free and private?
The math calculators are all free to use and fully private. Every tool in the suite works with no account, no payment and no usage cap. Because all of the maths runs client-side in JavaScript, the numbers you enter never leave your device, so there are no server round-trips and nothing is logged. That makes the tools fast enough to update as you type and safe to use for homework, coursework or private figures, even offline once the page has loaded.
Do I need to install anything?
Nothing needs to be installed. There is no download and no extension to add, and the calculators run in any modern browser on desktop, tablet or mobile. Open a tool, type your numbers, and read the step-by-step result instantly. Adding the page to your home screen is optional and simply creates a shortcut.
Do the calculators show the steps, or just the answer?
Every tool in the Math suite shows its working, not just the final number. The quadratic formula page shows the discriminant and both roots, GCF and LCM show the factor lists, and long division shows each bring-down step. The matrix tools keep their entries as exact fractions so each row operation can be checked. The goal is to let you verify homework or learn the method rather than trust a black box.