Tools

Handy single-page tools that run entirely in your browser.

41 pages

• Math & Conversions

  7 pages

  • Extended Euclidean Algorithm Calculator

    Extended Euclidean algorithm calculator: gcd and Bézout coefficients with a step table, modular inverse and modular exponentiation for big integers.

  • GCF & LCM Calculator

    Find the GCF (GCD, HCF) and LCM of 2 to 10 whole numbers, with the working shown by prime factorization, the Euclidean algorithm and listing factors.

  • Matrix Calculator

    Free matrix calculator with steps: determinant, inverse, rank, RREF, product and eigenvalues for matrices up to 6 × 6, in exact fractions.

  • Percentage Calculator

    Six free percentage calculators in one page: percent of a number, percent change, increase/decrease, and reverse percentage. Instant, no sign-up.

  • Permutation & Combination Calculator

    Free permutation and combination calculator: nPr and nCr with or without repetition, exact big numbers, step-by-step formulas and a list of outcomes.

  • Quadratic Equation Solver

    Solve quadratic equations step by step: discriminant, real or complex roots in exact and decimal form, vertex, factored form and graph. Free, no sign-up.

  • Unit Converter

    Convert miles, km, inches, pounds, stones, tons, °C, °F and kelvin with exact definitions and no rounding noise. See every unit at once. Free, in your browser.

• Grades & Study

  4 pages

  • Final Grade Calculator

    Find the score you need on your final exam to hit your target grade, with a grading-scale table and reverse calculator. Free, instant, runs in your browser.

  • GPA Calculator

    Calculate unweighted and weighted GPA from letter grades and credits, and project your new cumulative GPA. Free, instant, runs in your browser.

  • Grade Curve Calculator

    Curve test scores with a flat, scaled, square-root or boundary-shift method. See new scores, letter grades, statistics and a before-and-after chart.

  • Weighted Grade Calculator

    Calculate your class grade from weighted categories like homework, quizzes and exams, then see the average you need on the work that is still ungraded.

• Statistics

  4 pages

  • Confidence Interval Calculator

    Confidence interval for a mean (t or z, from summary statistics or raw data) or a proportion (Wilson and Wald), with steps and a number line.

  • Correlation & Covariance Calculator

    Calculate Pearson r, r², sample and population covariance, the regression line and Spearman's rho from paired data, with a scatter plot and working table.

  • Histogram Maker

    Paste your numbers to draw a histogram with automatic or custom bins, a frequency table and summary statistics. Download the chart as PNG or SVG.

  • Sample Size Calculator

    Work out how many people a survey or study needs from confidence level and margin of error, or find the margin of error of a sample you already have.

• Logic & Computer Science

  4 pages

  • Boolean Algebra Simplifier

    Simplify a Boolean expression or a list of minterms to its minimal SOP and POS with the Quine–McCluskey method. Free, runs in your browser.

  • Karnaugh Map Solver

    Karnaugh map solver for 2 to 5 variables: click cells or enter minterms, don't-cares or an expression and get the minimal SOP and POS with groups drawn.

  • Truth Table Generator

    Generate the truth table of any logical expression, check tautology and equivalence, and get the canonical DNF and CNF. Free, runs in your browser.

  • Two's Complement Calculator

    Convert numbers to two's complement in 2 to 64 bits, add and subtract binary with overflow detection, and convert fractions between binary, decimal and hex.

• Science

  5 pages

  • Chemical Equation Balancer

    Balance chemical equations, including ionic and redox equations. Get whole-number coefficients, an atom count, a mass check and the algebra step by step.

  • Molar Mass Calculator

    Calculate the molar mass of any chemical formula, see mass percent by element, and convert grams to moles and molecules. Free, runs in your browser.

  • Punnett Square Generator

    Draw a Punnett square for one, two or three genes and get the gametes, exact genotype and phenotype ratios and the probability of any outcome.

  • Resistor Color Code Calculator

    Decode 4, 5 and 6 band resistor color codes to ohms, tolerance and range, or enter a resistance to get its bands and the nearest E6, E12, E24 and E96 values.

  • Significant Figures Calculator

    Count significant figures, round any number to n sig figs, and add, subtract, multiply or divide with the correct rounding rules. Free, runs in your browser.

• Finance

  2 pages

  • Compound Interest Calculator

    Calculate compound interest with regular deposits, any compounding frequency, and inflation adjustment. Free, instant, and runs in your browser.

  • Loan Calculator

    Free loan calculator: get your monthly payment, total interest, payoff date and a full amortization schedule, with extra payments. Runs in your browser.

• Health & Fitness

  1 page

  • TDEE Calculator

    Estimate your Total Daily Energy Expenditure and calorie targets for weight loss, maintenance, or gain. Free, instant, and runs entirely in your browser.

• Text & Writing

  3 pages

  • List Compare

    Compare two lists online: find items in both, only in A, only in B, the union and duplicates. Ignores case, trims spaces, handles 50,000 lines in your browser.

  • Voice Dictation

    Dictate text with your voice in the browser: spoken punctuation commands in 5 languages, an editable transcript, copy, download .txt and read aloud.

  • Word Counter

    Count words, characters, sentences and paragraphs live, with reading and speaking time, top words and a length limit check. Free, in your browser.

• Typing & Skill Tests

  3 pages

  • Reaction Time Test

    Test your reaction time to a colour change or a sound over five tries and see your average, median and best result in milliseconds.

  • Typing Practice

    Learn touch typing with 30 step-by-step lessons, an on-screen keyboard with finger guides, live speed and accuracy, and drills for your weak keys.

  • Typing Speed Test

    Measure your typing speed in words per minute with a timed test: net and gross WPM, accuracy, a speed graph and your best results. Free, no sign-up.

• Developer & Design

  5 pages

  • Color Contrast Checker

    Check text and background colors against WCAG 2.x AA and AAA contrast rules instantly. Free browser-based tool — nothing is uploaded to a server.

  • CSV to JSON Converter

    Convert CSV to JSON or JSON to CSV in your browser: quoted fields, delimiter detection, type inference and a preview table. Nothing is uploaded.

  • JSON Formatter & Validator

    Format, validate and minify JSON online for free. Get exact line and column error locations, sort keys and check size instantly in your browser.

  • Regex Tester

    Test JavaScript regular expressions live: highlight matches, inspect capture groups and preview replacements. Free, instant, and runs entirely in your browser.

  • Subnet Calculator

    Find the network, broadcast, host range and mask of any IPv4 subnet, split a network into equal subnets and plan VLSM. Free, runs in your browser.

• Classroom & Teaching

  3 pages

  • List Randomizer

    Shuffle any list into a random order or pick N items at random. Fair Fisher–Yates shuffle, copy or download the result. Your list never leaves your browser.

  • Random Group Generator

    Split a list of names into fair random groups or teams, by number of groups or people per group. Even sizes, copy or print. Names never leave your browser.

  • Random Name Picker

    Pick a random name from your class list with no repeats until everyone has had a turn. Animated pick, history and undo. Names never leave your browser.