UD5 Toolkit
World Voltage & Frequency Reference – 110V vs 230V
Check the standard voltage and frequency for any country. Ensure your hair dryer, charger, or appliance is compatible before you plug it in abroad.
Tag: Word Frequency Counter - Analyze Text
24+ toolsFrequency Ratio to Cents Converter – Online Microtonal Tool
Convert a frequency ratio (e.g., 3/2) to cents and vice versa. Explore just intonation and microtones.
Compound Frequency Impact Calculator – Daily vs Monthly Compounding
Compare how different compounding frequencies (daily, monthly, quarterly, annually) affect the final amount of your investment or loan. Visualize the power of compound interest.
Newsletter Frequency Impact Calculator – Subscriber Churn Risk
See how changing your newsletter from weekly to daily (or vice versa) may affect open rates and unsubscribes based on industry benchmarks.
Frequency to Wavelength Converter – c = λf Calculator
Convert between frequency and wavelength for electromagnetic and sound waves. Use the speed of light or custom wave speed to get precise results instantly.
Histogram Generator – Bins & Frequency Distribution Online
Turn a list of numbers into a histogram. Choose the number of bins or let the tool auto-calculate using Sturges' rule. Visualize your data distribution instantly.
Online Frequency Sound Generator – Pure Tones & Sweeps
Play pure sine, square, sawtooth, or triangle waves at a precise frequency. Can sweep between two frequencies for testing speakers or hearing.
Piano Key Frequency Finder – Note to Hz & MIDI Number
Select a piano key to see its frequency in Hz and MIDI note number. Great for tuning, synthesis, or music theory exploration with interactive keyboard.
Drum Shell Fundamental Note Calculator – Online Bearing Edge
Enter drum diameter, depth, and material to find the shell's approximate fundamental note. For tuning reference.
Online Hearing Range Test – Frequency Sweep Hz
Play a frequency sweep from 20Hz to 20kHz. See where your hearing cuts off. Headphones needed.
Online Hearing Test – Frequency Pitch Perception
Play pure tones at various frequencies to estimate your hearing range. Simple and educational.
Character Frequency Analyzer - Online Visual Heatmap of Text
Analyze letter/symbol frequency with an interactive bar chart and heatmap. Useful for breaking simple ciphers, linguistics, and SEO keyword analysis. Local processing.
Letter Frequency Analyzer - Online ETAOIN SHRDLU
Paste text to see a live letter frequency bar chart. Helps break substitution ciphers. All local analysis.
Electromagnetic Spectrum Explorer - Online Wavelengths
Zoom through the electromagnetic spectrum from radio waves to gamma rays. See wavelength, frequency, and applications. Static educational page.
Analyser Node Playground - Online Real‑Time Frequency & Waveform
Connect an audio source to an Analyzer Node and display frequency and time‑domain data. Learn Web Audio visualization.
Character Frequency Chart - Online Text Analysis
See a live bar chart of character frequencies as you type or paste text. Great for cipher cracking and linguistics.
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.
Online Spectrogram Viewer - Audio Frequency Visualizer
Load an audio file and see its spectrogram with frequency over time. Adjust resolution and color map. Discover hidden sounds.
Antenna Length Calculator - Online 1/4 Wave & Dipole Tool
Calculate antenna element lengths for a given frequency (or vice versa). Supports 1/4 wave, 1/2 wave, dipole. Useful for ham radio. Local only.
Virtual Dog Whistle – Online Adjustable Frequency Tone
Play a sine wave tone adjustable from 5kHz to 22kHz. Test your hearing and your dog's attention.
MIDI Note to Frequency Converter - Online Music Tuning
Enter a MIDI note number (0–127) or a musical note name and get the exact frequency in Hz. Piano keyboard picker.
Character Counter - Online Letter & Symbol Frequency Tool
Deep-dive into text with detailed character and letter frequency analysis. Supports multiple languages and includes whitespace control. Fast and private.
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.
Live Sound Frequency Detector - Online Audio Analyzer
Use your microphone to detect the dominant frequency of ambient sounds. Visualize the spectrum. Local Web Audio.