Concert pitch · Handmade crystal in Kreuzwertheim
432 Hz vs. 440 Hz
Two numbers, eight hertz apart, and an argument that has run for decades. Here is what actually changes when you retune — and how both numbers got here, which is a stranger and better story than the argument.
First things first
The short answer
The difference between A = 432 Hz and A = 440 Hz is about a third of a semitone. Retune, and every note moves down by that same small step, together. The intervals stay the same, the harmonies stay the same — it is the same music, sitting slightly lower. Side by side you can hear it: 432 sounds a touch darker, and many people say warmer. On its own, you couldn't tell which one is playing.
Both numbers are modern. 440 became the standard in 1939 because radio needed one shared reference. 432 goes back to a letter Verdi wrote in 1884 — and to a mathematical idea much older than that. Five studies have compared the two tunings directly, and they found calm in both — with every measurable difference between them, from heart rate to sleep, pointing towards 432.
So: taste, with real history behind it, and a gentle scientific lean. Plus one thing almost nobody knows — there is a real 432 in the sky, and it took a mathematician with a tuning fork to find it. We'll get there.
The size of it
Can you actually hear eight hertz?
"A = 440" means the A above middle C vibrates 440 times per second. That is all concert pitch is: an agreed meeting point, so that a piano and an oboe end up in the same place. It isn't a property of the music — orchestras have moved that meeting point many times, and the music always came along.
Move it to 432 and everything shifts down by 31.8 cents — a cent is a hundredth of a semitone, so just under a third of a semitone. Music is made of relationships between notes, and since all the notes move together, none of those relationships change.
Side by side, the difference is audible: 432 sits lower, a bit rounder. On its own — no. Without absolute pitch, nothing in a 432 recording gives it away. You would just hear music.
Two things are worth knowing before you trust your ears to an online comparison, though.
First: the easiest way to convert a 440 recording to 432 is to slow it down by 1.8 percent, and many online versions are made exactly this way. That makes the 432 version not only lower but also slower — and slower music sounds calmer at any pitch. Part of what people fall in love with in those videos is simply the tempo.
Second: the "pure", beat-free intervals people hope to find at 432 really do exist in music — but they come from temperament, the way the twelve notes are spaced inside the octave, not from where A sits. You can have perfectly pure intervals at 440 and ordinary piano tuning at 432. If that purity is what your ear is after, it is available at any concert pitch.
The history
Where 440 comes from
There was no original pitch. That is the first surprise in the history books.
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1740–1810
Old forks, all over the map
Old tuning forks survive, and they are all over the map. One from Handel's circle (1740) gives A = 422.5. One from 1780 gives 409. One linked to Beethoven gives about 455 — higher than any orchestra plays today. Versailles played around 390 in 1795; La Scala climbed to 451. Every city and every generation tuned to its own A.
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The 1800s
The climb — and the singers who paid
And pitch kept creeping upward, because slightly higher sounds slightly more brilliant, and brilliance fills concert halls. The people who suffered were the singers: the orchestra's A rose year by year, their top notes rose with it, and their voices didn't. That — not philosophy — is why France passed a law in 1859 fixing A at 435, the first legal pitch in history. Vienna made 435 international in 1885. Britain used 439.
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1834–1936
440: a measurement, then a radio signal
440 itself came from a measurement. In 1834, Johann Scheibler measured the orchestras of his day with an instrument he had built himself and proposed 440 to a scientific congress in Stuttgart. America adopted it early — the musicians' union in 1917, the industry in 1926 — and from 1936 a US government radio station broadcast a pure 440 Hz tone at two minutes past every hour, so that any orchestra in the country could tune to the radio.
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May 1939
One number for the radio age
In May 1939, delegates from five countries met at the BBC in London to settle the matter, because radio needed one number for everyone. Britain's 439 had a practical problem: it is a prime number, which made it awkward to generate with the electronics of the time. 440 divides cleanly, and America was already using it. So 440 it was; ISO wrote it into the standards in 1955.
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Today
Still drifting
That is the whole story of 440 — singers, committees, radio engineering and a prime number. And even now it isn't rigid: most big orchestras tune somewhere between 440 and 444, Berlin around 443, baroque ensembles a whole semitone lower at 415, Cuba around 436. Concert pitch is a meeting point, and musicians drift from it whenever it suits the music.
The other number
Where 432 comes from
432 starts with Verdi — though not quite the way the legend tells it.
In 1884, Verdi wrote to the music commission of the Italian government. He had watched pitch climb all his life and watched his singers pay for it, and he asked Italy to adopt the French 435. Then comes the sentence the whole later movement rests on. If the commission preferred, for mathematical reasons, to lower 435 to 432, then — Verdi wrote —
"The difference is so small, almost imperceptible to the ear, that I associate myself most willingly with this."
That is the founding document: a composer protecting his singers, and agreeing to 432 as a rounding. He never wrote about health, nature or the cosmos. But the "mathematical reasons" he mentions are real, and they are worth two minutes.
In 1713, the French physicist Joseph Sauveur proposed anchoring music to C = 256. Why 256? Because it is 2⁸ — pure doubling from one: 1, 2, 4, 8, 16, 32, 64, 128, 256. If C = 256, every octave of C is a whole number, all the way down to a single vibration per second. Physicists loved it; the arithmetic comes out clean.
And how do you get from C = 256 to A = 432? Here is the detail that usually gets lost: it depends on which tuning system you use. In old Pythagorean tuning, A sits a pure major sixth above C, at the ratio 27:16 — and 256 × 27/16 = 432, exactly. On a modern equal-tempered piano, the same A comes out at 430.54. So 432 is not a constant of nature; it is what you get when you combine Sauveur's 256 with one particular ancient tuning system. Use the modern system instead, and the famous number turns into 430.5.
For a century, that was all 432 was — a footnote to a footnote. What brought it back was a campaign. In 1988 the Schiller Institute, part of Lyndon LaRouche's political movement, started a petition to lower orchestral tuning to "Verdi's A". Famous singers signed. The Washington Post covered it in 1989 under the headline "Lyndon LaRouche's Pitch Battle". From there the number spread into the early internet, and the stories grew as it travelled: ancient temples, DNA, water crystals.
The most famous of those stories says the Nazis pushed 440 through in 1939, with Goebbels behind it. The dates alone don't work: America had been on 440 since 1917 and broadcasting it since 1936, and the 1939 conference met in London, at the BBC, with Germany as one voice out of five. There is no villain in the history of 440 — just committees. Which is duller, and true.
What is true about 432: the number itself has an old and genuinely remarkable pedigree — as a number. The Kali Yuga in Hindu cosmology lasts 432,000 years. Babylon counted in sixties, and our day still does: 86,400 seconds, which is 2 × 43,200. Count the tone per minute instead of per second and A = 432 even becomes 25,920 — the traditional figure for the precession of the equinoxes. The number runs through the old calendars wherever you look. But none of these were frequencies: nobody could measure vibrations per second before the 19th century.
432 the number is ancient. 432 hertz is young.
The evidence
What the studies found
There are real studies on this. Five of them compared the two tunings directly — and read together, they tell a story that neither side of the debate seems to have noticed.
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2019
Florence — the same music, twice
33 people heard the same music at both tunings, without knowing which was which. Their heart rates came down under both — and under 432 they came down further, almost five beats per minute. The listeners also reported feeling more focused and more satisfied after the 432 sessions.
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2020
Florence again — sleep
Patients with spinal cord injuries, whose sleep is often badly disturbed, listened to their favourite music before sleeping — retuned to 432 or left at 440. Their sleep improved markedly under 432.
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2020
Chile — the waiting room
42 patients waiting for a tooth extraction — music at 432, music at 440, or silence. Both music groups came out far calmer than the silent group, and equally so. But the stress hormone cortisol ended up lowest under 432.
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2022
Italy — nurses on shift
54 emergency nurses in the middle of the COVID pandemic, on shift. Anxiety eased in every music group, slightly more under 432 — and breathing and blood pressure eased measurably only in the 432 group.
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2025
Germany — 432 against 443
Cancer patients listened at 432 and at 443, the pitch German orchestras actually play. Hearts slowed under both, further under 432 — and the blood vessels relaxed under 432 in a way 443 didn't match. Anxiety, mood and fatigue improved under both tunings alike.
Now put the five together: heart rate, sleep, cortisol, breathing, blood pressure, blood vessels — six different doors into the body, five different groups of people, and behind every door where a difference appeared, it was 432 that came out ahead. Not once the other way around. The effects are modest and the groups were small — the researchers themselves want larger trials — but five out of five is five out of five.
And one more finding runs through all of them, and it is just as good news: the calm itself showed up in both tunings, every time music played. Whatever you tune to, the old prescription holds — slow music, and someone actually listening.
One last thing belongs here, because it is true: listening runs on expectation. The brain leans into what it expects to hear, and that reaches into the body — pulse included. So if 432 sounds warmer to you, that experience is real. It happens in you, which is where all music happens anyway.
Cousto · 1978
There is a real 432 in the sky
Now the part of the story that hardly anyone knows.
In 1978, the Swiss mathematician Hans Cousto took the oldest law in music — double a frequency and you get the same note, an octave higher — and ran it on the sky. Take a real period, say the Earth's year. Treat it as one very slow vibration: one cycle per year. Double it 32 times and it lands in the audible range: 136.10 Hz, a low C♯. We've written about that tone before — it's the one on our Year tone chime.
Here is the part that stopped us when we first calculated it ourselves. That C♯ sits in a scale whose A is 432.1 Hz.
Two roads, then. One begins with Sauveur's 256 and a Pythagorean sixth — pure number-play, three centuries old — and arrives at 432.0. The other begins with the Earth circling the sun, and arrives at 432.1. A tenth of a hertz apart. When people say "432 is the frequency of the Earth", this is the true thing they are half-remembering: Cousto printed 432.1 beside the year tone in 1978, and the number went off travelling without its context.
We wanted to know why the two roads meet — and the answer turned out to be the oldest thing in this whole story. A hertz counts swings per second, and the second is Babylon's instrument. The civilisation that counted in sixties cut the hour into sixties too — 86,400 seconds to a day — gave its legendary kings 432,000 years before the Flood, and left behind the 25,920 of the Great Year. The number 432 and the second itself are children of the same four-thousand-year-old arithmetic. Measure the year-tone with any other clock and the tone still sounds — doubling doesn't care about units — but the famous number vanishes from its label.
And the year is only one voice. Run the same doubling on the Earth's day, and you get a G whose scale puts A at 435.9 — Verdi's number, near enough, from the same planet with a different clock. The Moon's month gives 445.9. Venus gives 442.5. Cousto's thirteen tones imply thirteen different concert pitches, from 432 up to almost 450.
The sky doesn't have one A. It has a choir of them — and 432 sings the year.
The tone itself
Listening to it
So this is where the two numbers of our title finally part ways. 440 was agreed at a conference. 432 was defended with borrowed stories for forty years. But the year-tone was derived — and as long as the Earth takes a year to round the sun, that tone is simply there, thirty-two octaves below a low C♯, waiting for someone to raise it into hearing.
The chime sings the year-tone a few octaves above 136.1 Hz — the same note, carried higher. A tone loses nothing when it climbs an octave; it keeps its character and changes only its register.
From the workshop
Thirteen tones, thirteen honest numbers
Planetary Energy Chimes
Each chime is tuned to a tone derived from a real astronomical period — Cousto's arithmetic, checkable line by line. Among them rings the sky's own 432: the Year tone, whose tuning reference of 432.1 Hz is not a chosen number but a result. Hand-made, hand-tuned; the long, clear decay is the material doing the work.
See the Planetary Chimes →Read next: What Frequency Is OM?
Questions
432 vs. 440 FAQ
Is 432 Hz better than 440 Hz? +
In five direct comparison studies, calm improved under both tunings — and every measurable difference between them favoured 432: slightly slower heart rate, lower stress hormone, better sleep, easier breathing, softer vascular readings. The effects are modest and the studies are small; researchers are asking for larger trials. If your ear prefers 432, that preference is real and reason enough.
Can you hear the difference between 432 Hz and 440 Hz? +
Side by side, yes — the 432 version sits just under a third of a semitone lower: a shade darker, rounder, warmer. On its own, either tuning simply sounds like music; listeners without absolute pitch cannot name which one is playing. Note that many online comparisons are made by slowing the recording slightly, which lowers the pitch and relaxes the tempo at the same time.
Was music originally tuned to 432 Hz? +
Historical pitch varied far more than the modern debate suggests — surviving tuning forks range from A = 409 to A = 455, and opera houses drifted between 390 and 451. Precise frequency measurement only arrived in the 19th century. 432 was proposed in Italy in the 1880s as a lower variant of the French 435 standard; it was one chapter in a long, wandering history, not an ancient universal tuning.
Did the Nazis change music to 440 Hz? +
No. America adopted 440 Hz in 1917 and standardised it in 1936, broadcasting it hourly by government radio — years before the 1939 London conference, where Germany was one of five delegations meeting at the BBC. The Goebbels story first appeared in 1988 and is dismissed by historians of the period.
Does 432 Hz repair DNA or heal the body? +
There is no evidence for DNA repair or for any specific healing effect of a concert pitch. What research does show is gentle relaxation from slow, attentively heard music — in both tunings, with the body's measures leaning consistently toward 432 in small studies.
Why is A = 440 Hz the standard? +
An international conference in London recommended it in 1939 — radio needed one shared reference, America already used 440, and Britain's 439 is a prime number that early electronics struggled to generate. ISO confirmed it in 1955. Orchestras today still range from 440 to 444, and baroque ensembles play at 415.
Is 432 Hz the frequency of the Earth? +
There is a real connection: octave-doubling the Earth's year gives a C♯ whose scale places A at 432.1 Hz — this calculation, published by Hans Cousto in 1978, is where the idea comes from. The Earth's day, doubled the same way, implies A = 435.9 Hz; the Moon 445.9; Venus 442.5. The sky offers a whole set of pitches, and the year-tone's 432.1 is its genuine contribution to this debate.
- Giuseppe Verdi — letter to the music commission of the Italian government (1884): the plea for the French diapason normal of 435 Hz, and the "almost imperceptible" 432 passage quoted above.
- France, law of 16 February 1859 — the diapason normal, A = 435 Hz, the first legal pitch standard; adopted internationally in Vienna, 1885.
- A440 history — Scheibler's Stuttgart recommendation (1834); American Federation of Musicians (1917); American Standards Association (1936); WWV 440 Hz broadcasts (from 1936); the London conference at BBC Broadcasting House (May 1939); ISO Recommendation 16 (1955), ISO 16 (1975).
- Joseph Sauveur — scientific pitch, C = 256 Hz (1713); in equal temperament A = 430.54 Hz, via the Pythagorean major sixth of 27:16 exactly 432 Hz.
- The Washington Post — "Lyndon LaRouche's Pitch Battle" (27 May 1989): the Schiller Institute campaign for "Verdi tuning", begun 1988.
- Calamassi & Pomponi, Explore 15(4) (2019) — 33 volunteers, double-blind cross-over: heart rate fell under both tunings, further under 432 (−4.79 bpm); listeners reported more focus and satisfaction under 432.
- Calamassi et al., Acta Biomedica 91(4) (2020) — patients with spinal cord injuries, double-blind cross-over: sleep quality improved markedly under favourite music retuned to 432 Hz versus 440 Hz.
- Aravena et al., Journal of Applied Oral Science 28 (2020) — tooth extraction, three arms: anxiety eased equally under 432 and 440 (both far below silence); salivary cortisol lowest under 432.
- Diamanti et al., Acta Biomedica 93(4) (2022) — 54 emergency nurses during the COVID-19 pandemic, double-blind: anxiety eased in both tuning groups, slightly more under 432; respiratory rate and systolic blood pressure fell measurably only under 432.
- Hohneck et al., BMC Complementary Medicine and Therapies (2025) — randomised cross-over trial in cancer patients, 432 vs 443 Hz: heart rate and vascular measures eased further under 432; anxiety, mood and fatigue improved equally in both tunings.
- Hans Cousto — The Cosmic Octave (1978): the octave-doubling method and the tuning references of the planetary tones (432.1 Hz for the year tone, 435.9 Hz for the day tone).