Microphone Sensitivity Tester - Online Input Level Meter
See a live VU meter of your microphone's input level. Test if your mic is working and adjust gain. Privacy‑friendly.
UD5 Toolkit
Professional 10-band audio EQ with real-time frequency adjustment. Boost bass, tweak treble, and apply presets directly in your browser.
Presets
See a live VU meter of your microphone's input level. Test if your mic is working and adjust gain. Privacy‑friendly.
Interactive scale showing dB levels of everyday sounds with playable samples. Hearing safety.
Enter current ball size and target to find approx rubber bands required. Fun and satisfying.
Estimate how much agricultural lime or elemental sulfur to add to change soil pH by a target amount. Based on soil type and current pH. Educational.
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.
Create and dispatch custom events with detail. Listen on other elements. Understand pub/sub pattern in vanilla JS.
Enter log pile dimensions to calculate cords and face cords. Also estimate heat content in BTUs by wood species. Local reference.
Rotate a 3D cube on your phone using the Gyroscope API. See angular velocity around each axis. Amazing sensor demo.
Calculate resistor values for transistor fixed bias or voltage divider configuration. Quick quiescent point analysis.
Track your subscriptions, calculate monthly and yearly totals, and find savings by pausing unused services. Local data.
Understand how !important behaves inside @layer vs unlayered styles. Interactive example. Avoid common pitfalls.
Build a proper <meta name='viewport'> tag with width, initial‑scale, and user‑scalable options. Avoid common mobile rendering issues.
Calculate how much water to change weekly to keep nitrates under control. Based on current nitrate level, desired level, and tank volume.
Type a line and see syllable count as you write. Generate nature-themed prompts. Poetry aid.
Calculate the output voltage and resistor values for a voltage divider circuit. Includes schematic. Handy for electronics hobbyists and engineers.
Enter a CSS value in vw/vh and see the actual pixel size at current viewport. Dynamic resize demo.
Input camera sensor, focal length, aperture, distance to get hyperfocal distance and DoF range. Visual chart.
Find the optimal TV size for your room or the best viewing distance based on screen size and resolution (1080p, 4K, 8K). Simple THX/SMPTE reference.
Calculate grout needed (lbs or kg) based on tile size, grout joint, and area. Also recommend spacer size. Local estimator.
Find out how large you can print based on image resolution in pixels. Understand DPI and megapixels.
Calculate how much pure ammonia to add to reach 4ppm for a fishless cycle. Safe start guide.
Enter a package name and version range to see all satisfying versions from the registry. Understand ^ and ~.
Enter tank volume and recommended dose to find exact ml or capfuls needed. Avoid overdosing fish.
An on‑screen ruler that measures in pixels, centimeters, and inches. Drag to resize. Handy for UI designers and developers.
Calculate how many planks you need to cover an area given plank dimensions and gap. Quick carpentry estimator. Local only.
Calculate how much fertilizer to add based on desired N‑P‑K ppm and water volume. For hydroponics and soil growers.
Count syllables per word and for entire text blocks. Ideal for writing haikus, poetry, and literacy exercises. Local algorithm.
Perform arithmetic on fractions and get simplified results. Handles mixed numbers and improper fractions. Step-by-step display. Educational and precise.
Calculate corrected (adjusted) age for premature infants based on birth date and due date. Important for developmental milestone tracking. Local only.
Convert diopter strength to approximate magnification and working distance for macro photography.