Hertz Detector identifies the dominant frequency of any audio playing in your current browser tab. See Hz values update in real time, identify musical notes, and visualize the full frequency spectrum — all without leaving your browser. Works with any audio source: music, videos, instruments, test tones, podcasts, and more.
Features
- Real-time Hz detection Detects the dominant frequency of audio playing in the active tab and displays the Hz value updating live.
- One-click detection Click "Detect" and immediately see the frequency. Free tier runs for 10 seconds per detection.
- Musical note identification PRO Identifies the closest musical note (12-TET equal temperament) with cents sharp/flat tuning accuracy. Great for tuning instruments or identifying pitches.
- Live spectrum visualizer PRO A real-time frequency spectrum display showing the full audio breakdown from 20 Hz to 5 kHz with labeled frequency axis.
- Multi-frequency peak detection PRO Detects and ranks multiple simultaneous frequencies with their Hz values, musical notes, dB levels, and relative magnitude bars.
- Always-On mode PRO Auto-detects audio continuously across tab changes. No need to manually start detection each time.
- Unlimited detection time PRO No 10-second limit. Detect for as long as you need with full start/stop control.
How to Use
- Install the extension from the Chrome Web Store and pin it to your toolbar.
- Play some audio in a browser tab — a YouTube video, a music stream, a test tone, or anything with sound.
- Click the Hertz Detector icon in your toolbar to open the popup.
- Press "Detect" to start frequency detection. The Hz value updates live as the audio plays.
- Read the results. The dominant frequency is shown in large green text. Pro users also see the musical note, spectrum visualizer, and detected frequency peaks.
- Stop detection manually (Pro) or wait for the 10-second auto-stop (Free). Detection stops automatically if you close the popup.
Pro upgrade: Unlock musical note detection, the live spectrum visualizer, multi-frequency analysis, Always-On mode, and unlimited detection time for a one-time payment of $9.