UD5 Toolkit
Tangram Puzzle - Online Drag & Match Shapes
Drag the seven tangram pieces to form a target silhouette. Multiple puzzles. Develop spatial thinking. All canvas interactions.
Educational Tools - School & Teaching
99+ toolsElephant Toothpaste Demo Calculator - Online Reaction Ratios
Find safe mixing ratios for the classic elephant toothpaste demonstration. Volume adjustments for different container sizes.
Polygon Name Finder - Online How Many Sides?
Enter a number of sides (3‑100) and get the correct polygon name (triangle, hectogon). Fun geometry reference.
Electron Configuration Writer - Online Orbital Diagram Tool
Get the full electron configuration and orbital box diagram for any element. Learn the Aufbau principle. Fast and local.
Flame Test Colors - Online Element Identification Chart
Click a metal ion to see the characteristic flame color and wavelength. Useful for analytical chemistry reference.
PRNG Validator - Online Check Randomness Pattern
Paste a list of numbers to visually check uniformity, mean, and simple pattern analysis. Educational tool for statistics and RNG.
ASL Fingerspelling Practice - Online Random Words Quiz
Shows a random short word and displays animated ASL fingerspelling letters. Type what you see. Improve receptive skills.
Periodic Table Explorer - Online Element Facts & 3D Model
Browse a beautifully designed periodic table with electron shell visualization and key facts. Click any element to learn more. Offline ready.
World Flag Quiz - Online Guess the Country by Flag
Random world flags shown; pick the correct country name from four choices. Score and streak. Learn geography.
Regex Visualizer - Online Railroad Diagram Generator
Enter a regular expression and see a visual railroad diagram explaining the pattern. Learn and debug regex.
Telescope FOV Simulator - Online Eyepiece & View Preview
Select telescope and eyepiece parameters to see the field of view circle on a simulated night sky image.
Bayes' Theorem Calculator - Online Probability Update Tool
Easily compute posterior probabilities given prior, likelihood, and marginal likelihood. Visual diagram. All local.
Roman Numeral Date Converter - Online MMXXVI Style
Convert any date into Roman numerals (day‑month‑year) for tattoos or special occasions. Clean and local.
Chemical Equation Balancer - Online Stoichiometry Solver
Enter an unbalanced chemical equation and get the balanced coefficients instantly. Supports parentheses and ions. All local JavaScript algebra.
Color Gamut Viewer - Online See sRGB vs Display P3
See the chromaticity diagram and compare sRGB, DCI‑P3, and your display. Fun for design geeks.
CSS Grid Playground - Online Interactive Layout Builder
Experiment with CSS Grid properties visually. Add rows, columns, and areas. See the grid in action and copy the code.
Julian Date Converter - Online Calendar to JD
Convert a Gregorian calendar date to its Julian Day Number and vice versa. Used in astronomy and mainframe computing.
JavaScript Type Checker - Online Typeof & Instanceof Sandbox
Paste any JavaScript expression and see its evaluated type and value. Understand JS coercion and type quirks. Educational.
Spirograph Simulator - Online Hypocycloid Drawing Tool
Create beautiful Spirograph patterns by adjusting circle radii and pen position. Change colors and save as PNG. Relaxing math art.
Rock Cycle Interactive Diagram - Online Geology Model
Click through the rock cycle to see how each rock type transforms into another. Animated arrows and descriptions.
Pi Digits Viewer - Online Scrolling Infinite π
Scroll through thousands of pre‑computed digits of π. Search for a specific string of digits. For math lovers.
Magic Square Generator - Online Create n x n Constant Sum Grid
Generate magic squares of odd order (3x3, 5x5, …). See the sum constant and verify rows, columns, diagonals. Educational math toy.
Conway's Game of Life - Online Cellular Automaton Simulator
Run Conway's Game of Life on a canvas grid. Draw patterns, start/stop the evolution, and adjust speed. A mesmerizing zero‑player simulation.
Easter Date Finder - Online Computus Algorithm for Any Year
Find the date of Easter Sunday for any given year. Learn about the computus algorithm. Simple and accurate.
Pythagorean Theorem Calculator - Online Right Triangle Solver
Enter two sides of a right triangle and get the third. Also gives area and perimeter. Simple and visual.
Polygon Area Calculator - Online Irregular Shape Tool
Calculate the area of an irregular polygon by entering its vertex coordinates. Uses the shoelace formula. Pure math.
Bias Detector Tool - Online Check Text for Subjective Language
Analyze text for subjective and emotionally charged words. Helps identify potential bias in writing. Purely heuristic, local operation.
Radiation Converter - Online Gray Rad Rem & Sievert
Convert between units of absorbed dose and equivalent dose (Gray, Rad, Rem, Sievert). Educational and reference. Local calculation.
Country Facts - Online Quick Nation Info & Flag Tool
Look up quick facts about any country: capital, population, currency, flag, and continent. Static data, fast search. Great for travel and education.
Interactive Periodic Table - Online Chemistry Reference
An interactive periodic table of elements with detailed properties, electron configuration, and images. Excellent educational resource. All static data.
Text to Binary Converter - Online ASCII Bit Translator
Convert any text into its binary representation (8-bit per character). See the raw bits. Suitable for learning computer fundamentals. All local.
Promise State Viewer - Online Check Resolve & Reject
Create promises that resolve or reject after a delay. See state changes and chain .then/.catch. Debug async code.
Image FFT Visualizer - Online See Frequency Domain
Upload an image and see its 2D FFT magnitude and phase. Learn how image filtering works. Educatinal tool. Canvas.
Piano Sight Reading Trainer - Online Random Note Staff
A random note appears on the grand staff; click the correct piano key. Improve sheet music reading. Multiple clefs.
Virtual Rock Tumbler - Online Stone Polishing Simulator
Experience the four stages of rock tumbling virtually. Start with rough stones and watch them polish over 'days'. Satisfying.
3D Perspective Box Drawer - Online Isometric Cube Tool
Draw a 3D box or room interior by dragging vanishing points. Great for learning perspective drawing. Export as image.
Handwriting Worksheet Generator - Online Traceable Letters
Create custom traceable handwriting worksheets with name or sentence. Print in dotted font. Great for teachers and parents.
Alphabet of Elements - Online A‑Z by Chemistry Symbol
See all elements sorted alphabetically by symbol. Picture and atomic weight. Beautifully styled static list.
Etymology Quick Lookup - Online Word Origin Reference
Enter an English word to get a brief etymology (Latin, Greek, etc.) and root meaning. From curated static data.
Kanji Stroke Order - Online Japanese Character Animator
Paste a Kanji and watch it drawn stroke by stroke with numbered sequence. Excellent for learners. Static data set.
Local Typing Race - Online Side‑By‑Side Word Competition
Two players type the same text on the same keyboard (WASD vs Arrow zones) and race to finish first. Fun classroom game.
Solubility Rules Reference - Online Quick Chemistry Table
Classic solubility rules for ionic compounds in water. Determine if a salt is soluble or forms a precipitate. Static guide.
pH Scale Explorer - Online Interactive Acid Base Chart
Drag a slider along the pH scale to see examples of solutions at that pH and the concentration of H⁺ and OH⁻ ions.
Confidence Interval Calculator - Online Mean & Proportion
Compute confidence intervals for a population mean (known/unknown sigma) and proportion. All popular Z/T values. Local.
Significant Figures Counter - Online Sig Fig Calculator
Count significant digits in a number and round to a specific number of sig figs. Perfect for chemistry and physics labs.
Constellation Sky Viewer - Online Star Map & Mythology
Click on a constellation to see its star pattern and read the Greek mythology behind it. Beautiful CSS illustration.
Polygon Centroid Calculator - Online Center of Mass
Find the centroid (center of mass) of any convex polygon by entering vertex coordinates. Useful for physics and design.
Molar Mass Calculator - Online Molecular Weight Tool
Enter a chemical formula (e.g., H2O, C6H12O6) and calculate its molar mass. Handles parentheses and hydrates. Pure frontend.
Function Graph Plotter - Online Math Visualizer 2D
Plot one or more mathematical functions f(x) on a 2D canvas. Zoom, pan, and see intersections. Great for calculus and algebra. Purely client‑side.
Flashcard Maker - Online Create & Study With Spaced Repetition
Create custom flashcards and review them with a simple spaced repetition algorithm. Data stored in your browser. No sign-up required.
Text to Morse Code Decoder - Online CW Translation Tool
Translate text to Morse code with audio playback. Adjust speed and tone. An educational tool for amateur radio enthusiasts. Works offline.
Online Tone Generator - Audio Frequency & Sound Wave Tool
Generate pure audio tones of specific frequencies (Hz). Adjust waveform type (sine, square, sawtooth). Ideal for audio testing and science experiments.
Flexbox Playground - Online CSS Flex Layout Generator
Visually experiment with Flexbox container and item properties. See the layout update in real time and copy the CSS. Learn by doing, fully interactive.
Binary to Text Converter - Online Decode Bits to String
Paste binary sequences and convert them back to readable text. Supports space-separated and 8-bit formatted strings. Quick encoding reconversion.
Popover API Demo - Online No‑JS Tooltips & Menus
Test the new HTML popover attribute for creating accessible tooltips, menus, and dialogs without JavaScript. Copy code snippets.
US States & Capitals Quiz - Online Geography Game
Test your knowledge: given a state name, pick its capital. Timed, with scoreboard. Learn all 50. No login.
Pixel Data to BMP Generator - Online Raw Image Builder
Enter RGB values row by row and create a tiny BMP file. Understanding bitmap headers. Geeky developer tool.
Clinical Color Blindness Tester - Online Ishihara Plate Style
View a series of digital Ishihara‑style plates. Not a diagnostic tool, just educational. Read numbers.
Molecular Geometry Viewer - Online VSEPR 3D Sketch
Select bonding and lone pairs to see the predicted shape (trigonal bipyramidal, octahedral). Static diagrams.
Atom Builder 2D - Online Create Elements with Protons/Electrons
Drag protons, neutrons, and electrons onto a Bohr model template. See the element change. Educational tool.