UD5 Toolkit
Student Loan Deferment & Forbearance Calculator
See how pausing your student loan payments through deferment or forbearance affects total interest and payoff date. Compare to continued partial payments.
Educational Resources & Tools
99+ toolsReverse Chord Finder – Name That Chord from Notes
Input the notes you're playing and get all possible chord names, including inversions and slash chords. A lifesaver for songwriters and music theorists.
Musical Interval Identifier – Ear Training & Theory Tool
Select two notes to instantly name the musical interval between them. Displays semitone count and common enharmonic spellings. Essential for music theory students.
Trigonometry Calculator – Sin, Cos, Tan & Inverse Functions
Compute sine, cosine, tangent, and their inverses. Input degrees or radians to instantly get exact values or decimal approximations for any angle.
GCD & LCM Calculator – Greatest Common Divisor & Least Common Multiple
Find the greatest common divisor and least common multiple of two or more numbers. Uses prime factorization and Euclidean algorithm with step-by-step output.
Factorial Calculator – n! for Integers & Large Numbers
Compute the factorial of any positive integer up to 170+ with full precision output. Also shows double factorial and explains the multiplication steps.
Gravitational Potential Energy Calculator – PE = mgh
Compute the gravitational potential energy stored in an object based on mass, height, and gravity. Ideal for physics students and engineering quick checks.
Kinetic Energy Calculator – KE = ½mv² Online
Calculate the kinetic energy of a moving object using mass and velocity. Supports units of kg, g, m/s, and km/h with instant conversion for physics homework and engineering.
Z-Score Calculator – Standardize Your Data Point
Find the z-score of a raw value given the population mean and standard deviation. Also computes the p-value and percentile for the normal distribution.
Fibonacci Sequence Generator – First N Terms & Golden Ratio
Generate the Fibonacci sequence up to any number of terms. Displays each term, ratios approaching φ, and a visual of the golden spiral for math enthusiasts.
Decimal to Mixed Number Converter – Simple Fraction Form
Turn a decimal number into a mixed number or improper fraction. Shows step-by-step simplification to help understand the conversion process better.
Today in Music History – Albums, Birthdays & Events
Discover notable music events, album releases, and artist birthdays that happened on this day in history. From classic rock to modern pop milestones.
Bodyweight Exercise Library – No-Equipment Workouts
Browse a collection of bodyweight exercises with animated illustrations and instructions. Filter by muscle group and difficulty to build your own home workout routine.
Hangul Syllable Combiner – Online Korean Block Builder
Select initial, medial, and final consonants to build a Korean syllable block. See its pronunciation.
Random Useless Fact Generator – Learn Something Weird
Press a button to get a random, surprising, and utterly useless fact. Perfect for icebreakers, curiosity, or just a quick mental break during your day.
Coleman-Liau Index Calculator – Readability Grade Level
Analyze your text using the Coleman-Liau Index to determine the U.S. school grade level needed to understand it. Paste or type text for instant readability feedback.
Verb Conjugation Driller – Online Random Tense & Pronoun
Select a common verb and drill its conjugation across tenses. Type the answer. Great for Spanish/French learners.
Automated Readability Index (ARI) – Online Readability Check
Compute the Automated Readability Index to gauge the difficulty of your text. Outputs a grade level required to understand the content. Great for educators and writers.
Bayes' Theorem Updater – Online Simple Probability Tool
Enter prior, likelihood, and marginal to compute posterior probability. Intuitive sliders for learning.
Mnemonic Sentence Builder – Online Create Acrostics
Enter a list of words to remember and generate a sentence where the first letters match. Silly but effective.
World Currency Viewer – See Banknotes from Random Countries
Explore banknotes from around the world. Click to see a random note with its country, denomination, and a brief description of the imagery.
Semaphore Flag Signal Trainer – Online Random Letter Drill
A random letter appears; you must select the correct semaphore position from 4 choices. Scouts & maritime.
Analog Clock Reading Quiz – Online Time Telling Practice
Random time displayed on an analog clock face. Type the time. Excellent for young students.
Ear Equalization Method Finder – Valsalva, Frenzel & BTV
Describe your equalization difficulty and current technique to get a recommendation for which advanced method (Frenzel, BTV) to learn next.
Weird Animal Fact Generator – Kid‑Friendly & Illustrated
Get a weird but true animal fact with a cute illustration. For example: 'A group of flamingos is called a flamboyance.' Learn while giggling.
Science Fair Project Idea Generator – By Grade Level
Select your grade and get a random science experiment idea with a hypothesis, materials list, and procedure. Perfect for last‑minute fair prep.
Interactive Circle of Fifths – Key Signatures & Chords
Explore the circle of fifths interactively. Tap a key to see its signature, relative minor, and chord family. The ultimate harmony reference for musicians.
Poker Hand Ranker – Identify Your Hand Instantly
Select your five cards and instantly see your poker hand ranking. Learn the hierarchy from high card to royal flush with this quick reference for Texas Hold'em players.
Student Loan Repayment Calculator – Standard vs IDR Plans
Estimate monthly payments under different student loan repayment plans including Standard, Graduated, and Income-Driven Repayment (IDR). Compare total interest paid over time.
Chord Ear Trainer – Identify Major, Minor, Dim & Aug by Sound
Listen to a chord played with a piano sound and select the correct chord type. Tracks your accuracy and gradually introduces seventh chords.
Bill of Rights Matching – Amendment to Description
Match each of the first ten amendments to its simplified description. A quick civics refresher for students and citizenship test prep.
Growth Mindset Quote Generator – Inspire Resilience
Press a button to get a child‑friendly quote about effort, persistence, and learning from mistakes. Perfect for classroom or morning meetings.
Active ↔ Passive Voice Converter – Rewrite Sentences
Convert a sentence from active voice to passive voice and vice versa. Helps you understand and practice the grammatical structure for clearer writing.
Today in Random History – Explore Events from the Past
Get a random historical event that occurred on this day or any day of the year. Learn something new and share it as a conversation starter.
Animal Sound Guessing Game – Listen & Identify
Play an animal sound and choose the correct animal from a grid. A fun listening game for kids and adults with dozens of familiar and exotic creatures.
Percentage to Fraction Converter – Simplify Math Instantly
Convert any percentage to a simplified fraction and decimal. Great for students learning math, teachers preparing materials, or anyone who needs a quick conversion.
Atbash Cipher – Reverse Alphabet Encryption
Apply the ancient Atbash cipher (A→Z, B→Y) to any text. Since it's self‑inverse, encoding and decoding use the same function. Fun for code puzzles.
Rhyme Scheme Labeler – Online AABB, ABAB Detector
Paste a poem and click to assign rhyme letters (A, B, C) based on end words. Understand structure.
Multiplication Flashcard Practice – Timed Math Drills
Practice times tables with interactive flashcards and a countdown timer. Choose specific numbers to drill, track your score, and improve mental math speed.
Emotion Identification Game – Learn Facial Expressions
Match faces to emotions in a simple quiz format. Helps children and individuals with autism practice recognizing and naming feelings.
Analog Clock Reading Practice – Tell Time to the Minute
Generate random analog clock faces and type the correct time. Adjust difficulty from hours only to 5‑minute intervals to full minute precision.
Lesson Plan Timer – Keep Your Class on Schedule
Enter your lesson segments with durations and start the timer. Alerts signal when to wrap up and move to the next activity.
Daily Quran Verse Display – Random Ayah with Translation
Display a randomly selected verse from the Quran with English translation each day. A moment of spiritual reflection and knowledge.
Rounding Mountain – Visual Number Line for Rounding
Type a number and see it on a number line with a “mountain” peak. Visualizes whether it should round up or down to the nearest 10, 100, or 1000.
Resistor Color Code Quiz – Test Your Electronics Knowledge
Practice reading 4‑band and 5‑band resistor color codes. Randomized challenges help you memorize the color‑digit mapping quickly.
Tesseract Rotation Simulator – Online 4D Cube Projection
A wireframe 3D projection of a rotating tesseract. Drag to rotate in 4D. Fascinating mathematical art.
Guitar Scale Visualizer – Fretboard Diagrams in Any Key
Choose a scale (major, minor, pentatonic, modes) and a key to see all five CAGED positions on an interactive fretboard. Notes and intervals labeled.
Dvorak Layout Text Converter – Online See Typed Words in QWERTY
Type on your QWERTY keyboard and see the text as if you were on a Dvorak layout. Helps learn Dvorak without switching.
Virtual Circular Slide Rule – Online E6B Style Calculator
Drag the virtual ring to perform multiplication, division, and unit conversions. Rediscover pre‑electronic calculator charm.
Cat Breed Identification Quiz – Online Photo & Name Match
See a cat photo and choose the breed. Learn iconic breeds like Siamese, Maine Coon, etc.
Pitot‑Static Tube Simulator – Online Airspeed & Bernoulli Principle
Adjust speed and see how dynamic pressure changes. Visualize how a pitot tube measures airspeed. Aviation & physics demo.
Did You Know? Fun Fact Quiz – True or False Challenge
Read a surprising statement and decide if it's true or false. Score points and learn quirky facts about science, history, and nature.
Day of the Week Finder – What Day Was July 4, 1776?
Enter any past or future date and instantly learn the day of the week. Uses the Zeller’s congruence algorithm for accurate results.
Syllogism Logic Checker – Online Categorical Logic Validator
Enter two premises and a conclusion (All A are B, Some C are not B, etc.) to check validity using Venn diagram rules.
Reading Log – Online Track Minutes & Books Completed
Simple interface for kids to log reading minutes and pages. Add book titles. Print weekly report. Local.
Essay Outline Generator – Online Build Thesis & Arguments
Fill in a thesis statement, arguments, evidence, and get a structured essay outline. Print.
Class Attendance Tracker - Online Log Present / Absent Percentage
Track attendance for multiple subjects. Mark present/absent and see percentage. Data in localStorage. Simple student tool.
US State Abbreviation Trainer – Online 2‑Letter Codes Drill
Randomly given state names, type the 2‑letter postal code. Track accuracy.
Element Abbreviation Typing Game – Online Symbols Race
The element name appears, type its symbol as fast as possible. Beat your high score.
Constellation Mythology Cards – Online Random Greek Story
Randomly displays a constellation with its art and the associated myth from Greek or other cultures.