Frequency Detector Tool

Frequency Detector Tool is a free, elegant frequency and musical-key analyzer for

producers, mixing engineers, sound healers, and the musically curious.

Type in any frequency in Hertz — like 315, 2.5k, or 29834 — and instantly see:

The musical note it maps to (e.g. A4 = 440 Hz)

How many cents sharp or flat it is

Whether it's IN KEY for the key you've selected

The nearest "cut candidate" — the closest out-of-key frequency

Vocal context notes to guide your EQ decisions

Pick your key from all 12 tones and the whole analysis updates instantly, showing

the in-key snap, the nearest cut, and vocal-range context (like the "Mud Zone"

around 250–400 Hz).

Open the full frequency chart to see every note across octaves 0–7, laid out for

boosting and cutting in your chosen key — scroll to explore the entire spectrum.

Also included:

Clickable Solfeggio frequencies (432, 528, 639, 741, 852, 963) with a note on

what each is associated with

"Did You Know?" music-theory facts

A calm, sacred-geometry inspired interface

Frequency Detector Tool is completely free — no ads, no subscriptions, no catch.

It's my first app, made with love. If it helps you, an optional donation on

eyeheru369.com supports more free tools.

Works on iPhone, iPad, and Apple Vision Pro.