Solfeggio Frequencies: Hear the Nine Tones and Check the Claims

By the Awaken Library Editorial TeamEditorial Team · Updated October 20, 2026Oct 20, 2026 · How we write

Solfeggio frequencies are nine tones from 174 to 963 Hz, sold as an ancient healing scale. The syllables are medieval; the numbers date from 1999 and later, and none has been tested on its own.

Solfeggio frequencies list and chart

The note column is our own calculation from standard tuning (A = 440 Hz); a cent is a hundredth of a semitone, so ±50 cents means halfway between two piano keys.

Only 741 Hz lands within 5 cents of a piano key. Four of the nine (285, 639, 852, 963 Hz) sit 40 or more cents off, close to halfway between two keys. No claim in that column has a study behind it; the studies that do exist are covered next. If you came to pick one for tonight: any of them, quietly, with the 20-minute timer (more under sleep).

Where the word “solfeggio” comes from: the hymn Ut queant laxis

The name comes from solfège, the do-re-mi syllables, which come from a Latin hymn to John the Baptist. Tradition credits the text to Paul the Deacon in the 8th century. Here is the first verse, with the syllables in bold:

Ut queant laxis / resonare fibris / Mira gestorum / famuli tuorum, / Solve polluti / labii reatum, / Sancte Iohannes.

“So that your servants may, with loosened voices, sing the wonders of your deeds, clean the guilt from our stained lips, O Saint John.” In the melody, each of the first six lines starts one step higher than the last. Around 1028, the monk Guido of Arezzo described how he used this hymn to teach choirboys to sight-read: learn the start of each line, and you know how the six steps of the scale sound. Later centuries changed “ut” to “do” (credited to Giovanni Battista Doni in the 17th century) and added “si”, later “ti”, for a seventh note.

The syllables never had fixed frequencies. They name steps, not pitches: “mi” is the third step up from wherever you start. Nobody could put a number of hertz on a sung note in Guido’s time. The first measured frequency of a musical tone comes from Marin Mersenne in 1636, the tuning fork from 1711, and the word “hertz” itself from 1935.

Where the nine numbers come from

The six core numbers, 396, 417, 528, 639, 741 and 852, first appear in print in Healing Codes for the Biological Apocalypse (Tetrahedron, 1999) by Leonard Horowitz and Joseph Puleo. According to Horowitz, Puleo found them in the verse numbers of the Book of Numbers, chapter 7, verses 12 to 83, by adding up digits. Those 72 verses list the gifts that twelve tribal leaders brought to the tabernacle, one leader per day, in the same words each time: a silver plate, a silver bowl, a gold spoon, animals for sacrifice. The book does not give a calculation anyone has been able to repeat; the digit sums of the verse numbers simply run 3, 4, 5, 6, 7, 8, 9, 1, 2 over and over.

What the nine numbers do share is a digit pattern. Add up the digits of any of them and reduce to one digit: you always get 3, 6 or 9, in that order up the list.

Most neighbors are exactly 111 Hz apart (174, 285, 396 …), with two exceptions: 396 to 417 is 21, and 639 to 741 is 102. The three numbers added later, 174, 285 and 963, fill the pattern in so that each digit 1 to 9 starts one number. That comes from writing the numbers in base ten; the same tone measured in another unit would have different digits. We could not find who added the last three or when.

Many popular pages say the numbers come from Gregorian chant or were “suppressed by the Church”. The suppression story comes from the 1999 book itself. We found no source before 1999 that gives these numbers.

Are the solfeggio frequencies a real scale?

No, and you can hear it. Guido’s six syllables go up in a fixed pattern: tone, tone, semitone, tone, tone. The six numbers from 1999 go up in very different steps. Here they are side by side, in cents (100 cents = one semitone):

The first step of the 1999 set, 396 to 417, is less than a semitone. The step that should be the small one, MI to FA, is the second largest. And the whole set spans 1326 cents, more than an octave, where Guido’s six notes fit in 900. Press “Play the 1999 set” in the player, then “Play a real ut-re-mi-fa-sol-la from 396” (396, 444.5, 498.9, 528.6, 593.3, 666 Hz) and compare: the second one sounds like the opening of a song, the first doesn’t.

Retuning the piano doesn’t turn them into a scale either. The 528 Hz page explains that 528 is an exact C only if you tune A to 444 Hz; at that tuning the other numbers still fall between notes. At A = 432 several of them land even further off.

Do solfeggio frequencies work? What the studies found

We searched PubMed on October 20, 2026. For 396, 639, 741, 852 and 963 Hz played as sound we found no studies at all. Almost everything that exists is about 528 Hz:

So do they work? As quiet sound to relax to, they work about as well as other quiet sound, which helps many people. As specific remedies, where 396 releases guilt and 741 detoxes, there is no evidence, because nobody has tested those claims. The only study that played the same music at a solfeggio number and at standard tuning had nine people.

Solfeggio frequencies for sleep and anxiety

There are no sleep studies of solfeggio tones themselves. There is good evidence about music in general: a 2022 Cochrane review of 13 trials with 1,007 adults with insomnia found that listening to music for 25 to 60 minutes a day improved self-rated sleep quality (by 2.79 points on a 21-point scale), with no harms reported. Those trials used ordinary relaxing music, not particular frequencies.

If you want to try a solfeggio tone at bedtime, pick the one you find least irritating, keep the volume low, and use the 20-minute timer instead of leaving it on all night. A bare sine tone gets tiring faster than music; if it does, a quiet music track is the same idea with less strain. For anxiety that lasts weeks or disturbs sleep, a sound is not a treatment; talk to a doctor.

“God frequency”, “forbidden frequency”, “7 healing frequencies”

These phrases fill search suggestions, and none of them has a clear source.

• “God frequency.” Most lists give it to 963 Hz, some to 432 or 528. Since 963 is one of the numbers added after 1999, the label is newer still. No religious text names a frequency.
• “Forbidden frequency.” Used in videos for 432 Hz, sometimes 528, with stories of bans that we could not find.
• “7 healing frequencies.” No fixed list. Sites give six, seven or nine numbers, and seven is usually chosen to match the seven chakras.

Solfeggio frequencies and the chakras

Charts pair the numbers with chakras: 396 the root, 417 the sacral, 528 the solar plexus, 639 the heart, 741 the throat, 852 the third eye, 963 the crown. The pairing joins two modern systems, the 1999 numbers and the 20th-century Western chakra chart. The Sanskrit texts on the chakras give each center a seed syllable such as LAM or YAM, not a frequency. Our guide to the seven chakras separates the old texts from what was added later.

Solfeggio frequencies vs binaural beats

They are different things that are often sold together. A solfeggio tone is one pitch, such as 528 Hz. A binaural beat needs headphones: each ear gets a slightly different tone, say 528 and 534, and the brain hears a slow 6 Hz pulsing that isn’t in either ear. Binaural beats have their own research, mostly on anxiety before surgery, and none of it depends on solfeggio numbers. The player has a binaural mode if you want to hear the difference.

How to listen safely

• Keep it quiet. The WHO counts 80 dB as safe for up to 40 hours a week and 90 dB for only 4. A tone left on for 8 hours every night is 56 hours a week; if you do it, keep it at the level of quiet speech or lower.
• High tones sound louder. At the same setting, 852 or 963 Hz can seem sharper than 174. Turn down when you switch up.
• Not near a baby’s bed. A 2014 test of 14 infant sleep machines found all of them were louder than 50 dB at 30 cm at full volume, the limit hospitals use for newborns, and three were louder than 85 dB; a phone playing a tone is the same kind of risk.
• Ringing ears or epilepsy. Stop if your tinnitus gets louder, and ask your doctor before using beating tones if you have epilepsy. More on this in the 432 Hz safety section.

What we don’t claim. None of the nine tones is shown to release guilt, detox, open a chakra or bring money; those labels came with the 1999 book, not from tests. Nine numbers with a digit pattern are not a treatment plan. Pick the one you like the sound of, or none.

How the player works

The player is the same one used on our 432 Hz page: your browser makes a sine wave with the Web Audio API, starting quietly and fading in and out to avoid clicks, with a timer, a volume control and an optional binaural mode. Nothing is downloaded or recorded. The two sequences play six tones of 1.2 seconds each: the 1999 numbers, and an equal-tempered hexachord built from 396 Hz with the steps 200, 200, 100, 200 and 200 cents. The note names, cents and digit roots in the tables are calculated when the page is built, with the same code the player uses.

Related: 528 Hz and the DNA claim · 432 Hz vs 440 Hz · the seven chakras