Speaker Test Tones - Online Left/Right Channel & Sweep
Play left‑only, right‑only, and frequency sweeps to test your speakers or headphones. Quick audio check.
UD5 Toolkit
Merge left & right channels — free, instant, private. No uploads leave your device.
Processing your audio...
Decoding and merging channelsPlay left‑only, right‑only, and frequency sweeps to test your speakers or headphones. Quick audio check.
Select original key and capo position to see the resulting chord shapes. Keep playing in the original key without barre chords.
Convert between common cooking units: cups → grams, teaspoons → ml, Fahrenheit → Celsius. Essential baking tool.
Calculate with binary numbers: addition, subtraction, multiplication, and division. Also bitwise AND, OR, XOR. Programmer's tool, fully client-side.
Convert minutes to decimal hours and vice versa. Essential for billing and payroll. Instant conversion with a handy chart.
Set media metadata and play/pause controls for the OS media widget. Test action handlers. Perfect for web audio apps.
Reference diagrams for USB‑A, USB‑C, micro‑USB pinouts. See wire colors and signal descriptions. Hardware hacking helper.
Convert network and data transfer speeds: bps, Kbps, Mbps, Gbps, KiB/s, MiB/s. A must when comparing internet plans. Fast and local.
Use priming sugar calculator adapted for kombucha. Prevent bottle bombs. Enter volume and desired fizz.
Paste a recipe ingredient list and double, triple, or scale to any serving size. Rounds fractions intelligently. Save your scaled recipes locally.
Find the correct wire gauge for speaker cables based on length and speaker impedance to avoid signal loss. Quick audio reference. Local.
Play reference pitches for standard ukulele tuning. Also works for baritone and other variations. Simple and local.
Enter a URL and click to check if it's reachable from your browser (CORS-limited, uses no-cors fetch). Quick manual test. Local only.
Create a personal countdown to any future date (birthday, vacation, launch). Shows days, hours, minutes, seconds. Locally stored.
Calculate your Basal Metabolic Rate using the Mifflin‑St Jeor equation. Know how many calories you burn at rest. All data private.
Log your coin collection with year, mint, and grade. Filter and sort. Data stored in localStorage. For numismatists.
Calculate the buying power of US dollars between any two years using official CPI data (updated annually). See how inflation erodes purchasing power. Local.
Add or subtract days, weeks, and months to find a future or past date. Also compute duration between two dates. Essential for project planning.
Enter two date‑time values and get the exact years, months, days, hours, minutes difference. Word output also.
Select component type and solder to see recommended iron temperature and tip shape. Avoid cold joints.
Calculate the salt percentage by weight for your vegetable ferments. Avoid mushy or unsafe ferments. Supports both dry salting and brine methods.
Send HEAD requests to popular websites and measure the round‑trip time. Quick network health check. Client‑side.
Reference for standard blanket and afghan sizes in inches and cm. Perfect for knitters and crocheters.
Convert dates between Hijri and Gregorian using the Umm al‑Qura algorithm. Approximate local moon sighting may vary.
Calculate ideal stereo speaker placement (toe-in, distance from wall) for best soundstage. Visual diagram. For audiophiles. Local tool.
Convert any PNG image into a proper .ico favicon file with multiple sizes embedded. For website icons. Local.
Convert hex or RGB to CIELAB L*a*b* values. Understand perceptual lightness and color opponents. Local math.
Shift the pitch of any audio clip by semitones without affecting playback speed. Perfect for music transposition. Local Web Audio.
Paste a human‑readable date (like 'next Friday' or 'March 5, 2023') and convert it to ISO 8601 format. Quick and tolerant.
Convert any image into colored ASCII art using divs with background colors. Creates a stunning text‑based replica. View & copy HTML.