Interactive Solfeggio & Pure Tone Frequency Synthesizer
Tap any reference frequency below (174 Hz – 963 Hz, including 432 Hz and 528 Hz) to synthesize a clean harmonic tone live in your browser.
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432 Hz vs. 440 Hz
Most modern music is tuned so that the A above middle C is 440 Hz. That standard was agreed internationally in 1939 and later published as ISO 16. Supporters of 432 Hz tuning argue that lowering A by 8 Hz gives music a warmer, more relaxed and more "natural" feel.
The difference is small: about 32 cents, roughly a third of a semitone. Most listeners cannot name which tuning they are hearing, although some say 432 Hz feels slightly softer when compared side by side.
History and myths
Concert pitch varied widely before standardisation, from below 420 Hz to above 450 Hz depending on the city and era. In the 19th century, the composer Giuseppe Verdi supported a slightly lower pitch, which is why 432 Hz is sometimes called "Verdi tuning".
Online you will also find claims that 432 Hz matches the "frequency of the universe" or that 440 Hz was chosen to make people anxious. These claims have no historical or scientific basis. The choice of 440 Hz was practical: orchestras and instrument makers needed one shared reference.
What research has found
Very little research exists. A 2019 double-blind crossover pilot study by Calamassi and Pomponi in Explore had 33 volunteers listen to the same music tuned to 440 Hz and 432 Hz. Listening to the 432 Hz version was associated with a slightly lower average heart rate and participants reported feeling a little more focused and satisfied. It was a small pilot, so the results are a hint rather than proof.
Using 432 Hz for relaxation
- As a meditation tone: play it quietly with the soft shimmer on and focus on slow breathing.
- As a backdrop: layer it under a forest stream or birdsong for a calm, natural soundscape.
- To compare: play 432 Hz, then nearby tones in the Tones panel, and notice which you find most comfortable.
Frequently asked questions
Is 432 Hz better than 440 Hz?
Neither is objectively better. Some people find 432 Hz warmer, and one small pilot study found a slightly lower heart rate with 432 Hz music, but the evidence is limited.
Why is music tuned to 440 Hz?
It became an international standard in the 20th century so orchestras and instrument makers could share one reference pitch.
Is 432 Hz a Solfeggio frequency?
No. It is a tuning reference for the note A. It is often listed alongside the Solfeggio tones because both are popular in meditation.