Math & Science Calculators
Mathematical and scientific calculation tools for students, teachers, and professionals—from percentages and fractions through geometry, statistics, coordinate formulas, and core algebra.
Calculators
Professional tools with instant results
Percentage Calculator
Find what X% of Y is, what percent one number is of another, or reverse a percentage to recover the whole. Three classroom-ready modes with clear formulas.
Percentage Change Calculator
Apply a percent increase or decrease to a value, or reverse the change to recover the original. Distinct from measuring percent change between two known values.
Percent Error Calculator
Compute percent error and signed relative error from an experimental measurement and a nonzero theoretical value. Lab-ready absolute and relative views.
Ratio Calculator
Simplify a two-part ratio to lowest terms or split a total amount into shares that match the ratio. Integer GCD simplification with decimal fallback.
Proportion Calculator
Solve a/b = c/d for any missing term with cross-multiplication. Enter three known values and choose which letter to solve for.
Fraction Calculator
Add, subtract, multiply, or divide two fractions and simplify to lowest terms. See improper, mixed, and decimal forms with clear arithmetic steps.
Quadratic Equation Solver
Solve ax² + bx + c = 0 with the discriminant. See two real roots, a repeated real root, or clearly labeled complex conjugates—plus the parabola vertex.
Random Number Generator
Generate inclusive random integers or decimals in a range. Optional seed for reproducible class demos. Educational PRNG—not cryptographic security.
LCM & GCD Calculator
Find the GCD and LCM of two or more integers. Uses Euclidean GCD and pairwise LCM with clear running steps—ideal for fractions and scheduling problems.
Mean Median Mode Calculator
Calculate mean, median, mode, range, min, and max from a list of numbers. Handles even-count medians and multimodal datasets clearly.
Systems of Equations Calculator
Solve two linear equations in two unknowns with Cramer’s rule. See determinant checks and step-by-step status for unique, none, or infinite solutions.
Chemical Equation Balancer
Balance chemical equations like H2 + O2 = H2O. Get positive integer coefficients that conserve atoms on both sides.
Physics Force Calculator
Solve Newton’s second law for force, mass, or acceleration, and the constant-speed relations for speed, distance, or time.
Area Calculator
Find area for rectangles, triangles, circles, trapezoids, parallelograms, and ellipses. Pick a shape, enter dimensions, and see the formula used.
Perimeter Calculator
Find perimeter or circumference for rectangles, squares, triangles, circles, and regular polygons.
Circle Calculator
Start from radius, diameter, circumference, or area and recover every other circle measure.
Triangle Calculator
Solve sides, angles, area, and perimeter from SSS, SAS, ASA, or right-triangle inputs.
Rectangle Calculator
Find area, perimeter, diagonal, or a missing dimension from length, width, area, or perimeter.
Volume Calculator
Compute volume for boxes, cubes, cylinders, spheres, cones, pyramids, and prisms.
Surface Area Calculator
Find total or lateral surface area for common 3D solids with optional open bases on cylinders and cones.
Pythagorean Theorem Calculator
Solve for the hypotenuse or either leg in a right triangle using a² + b² = c².
Distance Formula Calculator
Find the distance between (x₁,y₁) and (x₂,y₂) with Δx, Δy, and the formula shown.
Slope Calculator
Compute slope m = (y₂−y₁)/(x₂−x₁) with vertical-line interpretation when Δx = 0.
Midpoint Calculator
Find the midpoint M = ((x₁+x₂)/2, (y₁+y₂)/2) between two coordinate points.
Standard Deviation Calculator
Compute mean, variance, and standard deviation from a comma-separated list with sample (n−1) or population (n) mode.
Variance Calculator
Calculate variance and standard deviation from a numeric list with clear sample vs population choice.
Probability Calculator
Compute basic probabilities including complements, independent intersections/unions, and conditional P(A|B).
Z-Score Calculator
Standardize a value with z = (x − μ)/σ and see an approximate percentile under a normal curve.
Confidence Interval Calculator
Build a confidence interval for a mean using sample size, spread, and confidence level with z critical values.
Sample Size Calculator
Estimate required sample size from confidence level, margin of error, and proportion or population SD.
Margin of Error Calculator
Compute margin of error from confidence level, sample size, and proportion or standard deviation.
Percentile Calculator
Find a percentile value from a data list using linear interpolation or nearest-rank method.
Quartile Calculator
Compute quartiles and interquartile range from a data list with your chosen percentile method.
Correlation Calculator
Compute Pearson correlation and r² from paired X and Y lists of equal length.
Linear Regression Calculator
Fit y = mx + b to paired data with slope, intercept, r, and r².
Weighted Average Calculator
Compute a weighted average from matching value and weight lists.
Exponent Calculator
Compute base raised to an exponent with domain checks for negatives and zero.
Square Root Calculator
Compute square roots or nth roots of a value with even-root domain checks.
Log Calculator
Evaluate log_b(x) using change-of-base with natural logs.
Factorial Calculator
Compute n! for non-negative integers up to 170.
Prime Factorization Calculator
Factor integers ≥ 2 into prime powers with trial division.
Absolute Value Calculator
Return the non-negative magnitude |x| of any real input.
Learn & Understand
In-depth guides and educational content
How Percentages Work: Of, Change, and Percentage Points
Learn the difference between percent-of questions, applying a percent change, measuring change between two values, and percentage points versus relative percent.
Fraction Arithmetic Basics: Common Denominators and Simplifying
Learn why fractions need common denominators to add, how reciprocals drive division, and how GCD simplification keeps answers in lowest terms.
Quadratic Equation Basics: Discriminants Before Roots
Learn how the discriminant classifies ax² + bx + c = 0 into two real roots, a repeated root, or complex conjugates—before you reach for a calculator.
Random Numbers Basics: Inclusive Ranges and Reproducible Seeds
Learn what inclusive random ranges mean, when a seed helps classroom demos, and why educational PRNGs are not cryptographically secure.
Systems of Equations Basics: 2×2 Linear Systems
Learn how two linear equations produce a unique solution, no solution, or infinitely many solutions using determinants.
Chemical Equation Balancing Guide: Atom Conservation
Learn how stoichiometric coefficients conserve atoms, why formulas must be correct first, and what balancing cannot prove.
Physics Force Basics: F = ma and Constant Speed
Learn when Newton’s second law applies, how to rearrange F = ma, and how constant-speed distance formulas differ from force problems.
Geometry Formulas Basics: Plane & Solid Figures
A concise overview of area, perimeter, volume, and surface-area formulas for common shapes—with when to use each.
Statistics Basics: Mean, Spread, and Inference
Understand sample vs population variance, z-scores, confidence intervals, and when independence matters in probability.
Exponents, Roots, and Logarithms
Powers, nth roots, and logarithms as inverse operations—with domain restrictions that calculators enforce.
Analytic Geometry: Distance, Slope, and Midpoint
Coordinate formulas linking two points in the plane—distance, slope (including vertical lines), and midpoint.
Latest Articles
Expert insights and analysis
Percent vs Percentage Points: Why the Wording Matters
A short guide to absolute percentage-point gaps versus relative percent changes—with examples from polls, interest rates, and grades.
How Fraction Worksheets Keep Results in Lowest Terms
A practical walkthrough of fraction operations: common denominators, reciprocals, GCD simplification, and when mixed numbers help or hurt.
How Quadratic Discriminants Classify Roots
Walk through D > 0, D = 0, and D < 0 with classroom examples—including why complex conjugates should be labeled instead of hidden.
Math.random vs Crypto Random: What Classroom RNGs Should Disclose
Why educational random number tools should document Math.random or seeded PRNGs—and when you must switch to crypto.getRandomValues instead.
How to Solve Two Linear Equations With Clear Determinant Checks
Walk through 2×2 linear systems: unique intersections, parallel contradictions, and dependent lines—using Cramer’s-rule triage students can verify by hand.
How to Balance Chemical Equations Without Changing Formulas
A practical guide to atom conservation, coefficients vs subscripts, and why a balanced skeleton is not the same as a real-world reaction.
How Newton’s Second Law Worksheets Stay Honest
Learn how F = ma worksheets separate net force from constant-speed distance formulas, and why unit consistency matters more than button presses.
Sample vs Population Standard Deviation Explained
A practical guide to choosing sample vs population variance and standard deviation—with classroom examples.
When to Use Z-Scores and Confidence Intervals
Z-scores locate one value on a bell curve; confidence intervals bracket a mean. This article keeps the jobs separate.
Pythagorean Theorem Beyond the Classroom
Why a² + b² = c² shows up in coordinate distance, ladder problems, and CAD diagonal checks.
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