• 01

  Percentage

  Calculate X% of Y, percentage change between two values, or percentage difference. Three modes in one calculator.

  Calculate →
• 02

  Average

  Find the arithmetic mean of any list of numbers. Also shows sum, count, minimum, and maximum.

  Calculate →
• 03

  Fraction

  Simplify a fraction to its lowest terms, or add two fractions and get the result in simplified form. Uses GCD reduction.

  Calculate →

• 01 Area Calculate the area of a circle, rectangle, triangle, trapezoid, ellipse, or parallelogram. Shows the formula used for each shape. Math →
• 02 Average Find the arithmetic mean of any list of numbers. Also shows sum, count, minimum, and maximum. Math →
• 03 Binomial Probability Calculate P(X=k), P(X≤k), or P(X≥k) for a binomial distribution B(n,p) using the exact PMF. Includes a PMF bar chart for up to 50 trials. Math →
• 04 Circle Find any circle measurement — radius, diameter, circumference, or area — from any single known value. Enter one quantity and get all four instantly. Math →
• 05 Confidence Interval Calculate the confidence interval for a population mean from your sample mean, standard deviation, and sample size at 90%, 95%, or 99% confidence. Math →
• 06 Coordinate Distance Calculate the distance between two points in 2D or 3D, plus the midpoint and slope. Supports negative coordinates. Math →
• 07 Distance Calculate the Euclidean distance between two points in 2D or 3D space. Math →
• 08 Exponent Raise any base to any power — positive, negative, or fractional — with domain error detection for undefined results. Math →
• 09 Fibonacci Find the Nth Fibonacci number or list the first N terms of the Fibonacci sequence. Supports up to F(100) with exact integer precision. Math →
• 10 Fraction Simplify a fraction to its lowest terms, or add two fractions and get the result in simplified form. Uses GCD reduction. Math →
• 11 GCF and LCM Find the Greatest Common Factor (GCF) and Least Common Multiple (LCM) of any list of integers using Euclid's algorithm. Math →
• 12 Geometric Sequence Find the Nth term and sum of a geometric or arithmetic sequence. Enter the first term, common ratio (or difference), and N to get results instantly. Math →
• 13 Law of Cosines Solve any triangle using the law of cosines. Enter three sides (SSS) or two sides and the included angle (SAS) to find all angles, area, and perimeter. Math →
• 14 Law of Sines Solve triangles using the law of sines. Supports ASA, AAS, and SSA modes. The SSA ambiguous case shows 0, 1, or 2 valid solutions automatically. Math →
• 15 Linear Equation Solve systems of 2 or 3 linear equations with step-by-step solutions. Detects unique solutions, no solution (parallel lines), and infinitely many solutions. Math →
• 16 Logarithm Calculate the natural log, log base 10, log base 2, or any custom base logarithm. Results to 6 significant figures with full domain validation. Math →
• 17 Lottery Odds Calculate exact lottery prize-tier odds for any pool size. See "1 in X" probability and percentage for the jackpot and every lower prize tier — configurable for Powerball, Mega Millions, or any lottery. Math →
• 18 Margin and Markup Calculate gross margin % and markup % from cost and price — both displayed together so you can see exactly how the two differ and avoid the most common pricing mistake. Math →
• 19 Matrix Calculate the determinant or inverse of a 2×2 or 3×3 matrix, or add and multiply two matrices. Guards against singular matrices (det = 0) with a clear error rather than NaN. Math →
• 20 Mean, Median and Mode Find the mean (average), median (middle value), and mode (most frequent value) of any list of numbers. Math →
• 21 Modulo Calculate the remainder of a division (modulo) for any integers, including negatives. Choose between truncated (JavaScript/C) and floored (Python) convention. Math →
• 22 Percentage Calculate X% of Y, percentage change between two values, or percentage difference. Three modes in one calculator. Math →
• 23 Percentage Change Calculate the percentage increase or decrease between two values. Handles positive, negative, and zero-result cases with clear directional output. Math →
• 24 Permutation and Combination Calculate nPr (ordered permutations) and nCr (unordered combinations). Handles very large n using BigInt — no silent Infinity. Math →
• 25 Prime Factorization Find the prime factorization of any number up to 10¹⁵. See the prime factors and exponent notation instantly. Math →
• 26 Probability Calculate simple event probability, the complement (probability of not A), or the joint probability of two independent events. Math →
• 27 Proportion Solve a proportion a/b = c/d for any unknown term. Enter the three known values and select which one is missing. Math →
• 28 Quadratic Equation Solve ax² + bx + c = 0 with a numerically-stable algorithm. Handles two real roots, one repeated root, and complex roots (no real solutions). Math →
• 29 Random Number Generate a random integer within any range you specify. Runs entirely in your browser — no server, no logging. Math →
• 30 Ratio Simplify a ratio to its lowest terms, or solve a proportion a:b = c:? to find the missing fourth term. Math →
• 31 Roman Numeral Converter Convert any integer from 1 to 3999 to Roman numerals, or convert a Roman numeral back to an integer. Validates both directions and rejects non-standard forms like IIII or VV. Math →
• 32 Rounding Round any number to a specified number of decimal places using half-up (standard) or half-even (banker's) rounding. Supports negative decimal places. Math →
• 33 Scientific A full-featured scientific calculator with basic arithmetic, square root, squaring, reciprocal, percent, and ±. Keyboard-accessible with roving focus navigation. Math →
• 34 Scientific Notation Convert numbers to and from scientific notation (m × 10^e). Supports 6 significant figures for the mantissa. Math →
• 35 Significant Figures Count significant figures in any number or round to N sig figs instantly. Handles leading zeros, trailing zeros, and scientific notation correctly. Math →
• 36 Slope Find the slope, y-intercept, equation, and angle of a line through two points. Handles vertical lines (undefined slope). Math →
• 37 Standard Deviation Calculate population and sample standard deviation and variance from a list of numbers. Uses the numerically stable two-pass algorithm. Math →
• 38 Triangle Solve a triangle from three sides (SSS), two sides and an angle (SAS), or a right triangle from two sides. Computes all angles, area, and perimeter. Math →
• 39 Weighted Average Calculate the weighted average of any set of values. Add rows, enter each value and its weight, and get the exact Σ(v×w)/Σ(w) result with a per-row breakdown. Math →
• 40 Z-Score Calculate z-scores, p-values, and percentiles from any observation using the standard normal distribution. Also find the z-score for any percentile (inverse). Math →