Productivity & Utilities

This is a productivity tool that alternates between 25 minutes of concentration time and 5 minutes of break time, and notifies you with a sound or desktop notification when the work is completed.

The entered name list will be shuffled, randomly divided into teams, and representatives will be selected using a roulette wheel.

Transcribes live audio from your microphone and appends finalized speech recognition results to an editable text area. Depending on your browser, audio may be sent to an external speech recognition service.

Create an original vocabulary book and perform memorization efficiently based on the timing of the forgetting curve (spaced repetition).

This is a rhythm/performance tool that plays a click sound at a precise tempo according to the specified BPM and time signature, and makes the screen blink.

This is a breathing method guidance tool that helps you meditate and relieve stress by following an animation that tells you when to breathe (inhale, hold, exhale).

Test your character input speed (WPM) and accuracy by accurately typing short English or Japanese Romaji texts within a time limit.

The surrounding volume (sound pressure level) from the microphone is collected in real time, and the simple decibel (dB) value of the entire environment is displayed on a meter.

Displays the entire screen in a single color (red, green, blue, white, black, etc.) and inspects the LCD monitor for missing dots, color unevenness, and light leakage.

Performs dice rolling, coin tossing, and generation of a random number list within a specified range with intuitive 3D-like animation.

A piano keyboard that runs on your browser. You can enjoy simple performances by selecting a sound wave waveform and assigning keys on your mouse or PC keyboard.

Randomly generate quizzes on addition, subtraction, multiplication, and division. It is optimized for print layout (A4), and you can also toggle display/hide of answers.

Enter the daily goals you want to make into a habit (exercise, study, etc.), check the calendar on the day you achieve them, and display a list of your continuation rates.

Display the current time in major world cities side by side in analog and digital format, and use the slider to compare time differences (meeting candidate times, etc.).

Based on height, weight, age, and activity intensity, obesity degree (BMI), basal metabolism (BMR), and total calorie expenditure (TDEE) are calculated and drawn on a visual meter.

You can create pixel art on a 16x16 or 32x32 grid, set layers and animation frames, and save it as a transparent PNG or GIF animation.

You can play the game by generating a random maze using an algorithm and manually aiming for the goal, or you can watch the automatic solving process of the search algorithm through animation.

While viewing public domain Western masterpieces in high quality, you can customize the frame style and exhibition room lighting, and extract the colors (HEX code) of each work.

You can create and save beautiful geometric art in real time by adjusting mathematical models such as fractals, chaotic orbits, and golden angle Fibonacci spirals.

This is a concentration BGM synthesis tool that allows you to blend white noise, pink noise, brown noise, and the sounds of rain, wind, and waves to your desired balance.

This is a tool that can measure lap times and split times infinitely in 1/1000 second units, graph average laps, highest/lowest laps, and export them as CSV files.

This is an educational illustrated book that visually displays detailed physical properties, electronic configuration (bohr model animation display), absorption and emission spectra, etc. by clicking on each element in the periodic table of elements.

View arrival local date and time along with time progression based on departure date and time, flight duration, and manual UTC offset or DST settings.

This is a 3D Rubik's Cube that uses CSS 3D Transforms and can be moved intuitively by dragging.

Play Reversi against AI across three difficulty levels, with relative evaluation heatmaps for candidate moves. You can also select hint depths of 1, 3, or 5 to analyze the board.

This is a tool that allows you to play Sudoku puzzles of different difficulty levels, or automatically answers input puzzles using a backtracking algorithm, and visualizes the search process with animation.

This is a portable sampler that allows you to record environmental sounds and voices from a microphone, and then assign them to a keyboard or drum pad to enjoy sampled performances.

A secure Kanban board task management tool that saves in LocalStorage, allowing you to move cards intuitively using drag and drop.

This is a tool that uses the Web Audio API to generate high-frequency sounds from 8kHz to 20kHz to easily measure and test ear age based on the hearing limit.

This is a classic brain training game (Simon) in which you memorize the pattern order of panels with lights and sounds, and correctly reproduce sequences that gradually become longer.

This is a tool that allows you to simulate Conway's Game of Life on your browser and observe the dynamic changes of cell birth and death.

This is a tool that allows you to play the classic 15 puzzles, or create a split puzzle from your own images, and enjoy the automatic shortest strategy animation using the A* algorithm.

It is a mind map editor that allows you to easily add nodes with key operations, organize the layout intuitively, and export it as SVG or PNG.

Manages your book collection directly in browser storage with manual entry support. Looking up an ISBN queries external services (openBD or Google Books), and loading cover images contacts their respective hosts.