What is the love frequency? Three tones share the name

Which frequency is called the love frequency?

Most often 528 Hz, though two other tones share the name. People who search for the love frequency usually mean the Solfeggio tone at 528 Hz, and Harmonance's own 528 Hz page carries the title Love and Renewal. The second is 639 Hz, the Solfeggio tone for relationships. The third is 221.23 Hz, the tone Hans Cousto worked out for Venus, the planet named for the Roman goddess of love.

The three come from different places. Two were read from the verse numbers of one chapter of the Bible; the third comes from the length of the Venus year. None of them was found by measuring love, closeness or kindness, and no study has played any of them to people and measured how they feel about each other.

This guide follows each number back to where it started, shows when it was first tied to love, measures what the three sound like from the site's own audio files, and sets out what research on music and closeness has actually found. The Feeling disconnected? page plays 639 Hz and the Venus tone side by side, so you can hear two of the three while you read.

Why is 528 Hz called the love frequency?

528 Hz was tied to love by a book, years after the number was first published, and the earliest records give it a different meaning. The number itself comes from a 1999 book by Leonard Horowitz, written with a researcher its publisher named as Joseph Barber, which offered six tones as the lost notes of a medieval hymn to St John the Baptist.

The method is arithmetic. Take the verse numbers of Numbers chapter 7 from verse 12 to verse 29, and add each number's digits down to a single figure: 12 gives 3, 14 gives 5, 29 gives 2. Write the eighteen figures in three rows of six and read down each column, and the columns spell 396, 417, 528, 639, 741 and 852. 528 is the third column, from verses 14, 20 and 26; 639 is the fourth, from verses 15, 21 and 27. The publisher's own press release from 1999 describes the method as "reducing the verse numbers to their single digit integers".

That press release matched each tone to a syllable of the hymn, the one the old note names UT, RE and MI come from. It says that "the third note, frequency 528, relates to the note "MI" on the scale", and reads MI as the start of mira gestorum, Latin for wonderful deeds. It does not mention love. Neither does an early list of the six tones, from Soma Energetics in 2002, which gives 528 Hz the word transformation and 639 Hz the words "Connecting/Relationships".

The earliest link to love that Harmonance could find in print is a later book. In 2011 Horowitz published The Book of 528, whose subtitle calls 528 the key of love, and the nickname has followed 528 Hz far beyond the book ever since. The guide to 528 Hz follows the book's other claims, including one about genetic material that has never been tested in people, and the five small studies that have played 528 Hz to listeners.

Where do 639 Hz and the Venus tone come from?

639 Hz comes from the same column arithmetic as 528 Hz, and the Venus tone from the time Venus takes to go round the Sun. They are linked with love for different reasons: 639 Hz through the word relationships, Venus through its name.

639 Hz is the fourth Solfeggio column, matched to the syllable FA. The 2002 list's "Connecting/Relationships" is where its reputation for connection begins, and Harmonance's page calls it 639 Hz, Connection and Communication. The guide to 639 Hz sets out those claims and the few small studies that have used the tone.

The Venus tone is arithmetic applied to a real orbit. NASA's Venus fact sheet gives the planet's sidereal orbit, once round the Sun against the stars, as 224.701 days. That is 19,414,166 seconds, so as a vibration it is one cycle in that time, about 0.0000000515 Hz. Double a frequency and it rises by one octave; double this one 32 times, which multiplies it by 4,294,967,296, and it reaches 221.23 Hz. Cousto's own tuning tables take the Venus year as 224.7008 days and give the same 221.23 Hz, an A.

The love comes from the name. In NASA's words, "Venus is named for the ancient Roman goddess of love and beauty, who was known as Aphrodite to the ancient Greeks." Cousto carried that meaning into his description of the tone. His German text reads:

Fördert die höhere Liebesenergie und das Harmoniebestreben.

In English: it furthers the higher energy of love and the striving for harmony. That is a description from a tradition, not a measurement. The guide to 221.23 Hz follows the Venus year further, and the Libra page plays the Venus tone as that sign's tone.

What do the three love frequencies sound like?

They are three different notes, and measured from the site's own audio, each is almost a pure tone. Harmonance measured the audio file each tone's page plays, 16 seconds of each, and the three played together at their pages' shared level.

The tones behind the chart

Tone	Nearest piano note	Place in the ear
221.23 Hz, Venus	A, 9.7 cents sharp	6.29 Cams
528 Hz	C, 15.6 cents sharp	11.12 Cams
639 Hz	D sharp, 46 cents sharp	12.39 Cams

Download the measurements (CSV)

On a piano tuned to A at 440 Hz, the Venus tone sits 9.7 cents above the A below middle C, where a cent is a hundredth of a semitone. 528 Hz sits 15.6 cents above the C an octave above middle C, and 639 Hz falls almost halfway between D sharp and E, 46 cents above the D sharp. Each page's file also carries two faint harmonics, at twice and three times the tone, 23.1 dB and 34 dB below it.

528 Hz and 639 Hz, played together, make an interval of 330.3 cents: a minor third, 30 cents wider than the piano's and 14.7 cents wider than the pure ratio of 6 to 5. The Venus tone sits an octave and a minor third below 528 Hz, 1,506 cents, only 6 cents from the piano's version of that interval.

The inner ear sorts sound by pitch into overlapping filters, and how two tones blend depends on how far apart they land among them. In 1965 Reinier Plomp and Willem Levelt played pairs of pure tones to listeners and found:

These intervals are evaluated as consonant for frequency differences exceeding critical bandwidth, whereas the most dissonant intervals correspond with frequency differences of about a quarter of this bandwidth.

Filter widths are counted in Cams, after the formulas of Glasberg and Moore, where each filter is one Cam wide. 528 Hz and 639 Hz are only 1.27 Cams apart, just over one filter, so on the roughness measure Harmonance uses for its own sound the pair scores 21.5% of the roughest possible pair of equal tones near 639 Hz. The page's own pair, 639 Hz with the Venus tone, sits 6.1 Cams apart and scores 2.1%. Its one close pair is the faint 3rd harmonic of the Venus tone, 663.69 Hz, which lands 24.69 Hz from 639 Hz in the same filter; measured, it moves the loudness of that part of the sound by 2% at 24.69 times a second.

The three do not sound equally loud at the same level, because the ear is less sensitive to low pitches. At the pages' shared level, the equal-loudness model (ISO 226) that Harmonance uses for its own sound gives the Venus tone 54.2 phon, 528 Hz 62.4 phon and 639 Hz 63.4 phon. When you mix them, the Venus tone is the one to bring up, or the other two the ones to bring down.

Can a sound make people feel closer?

Making music together can, at least for a while, but no study has shown that one pitch does. The research nearest to the idea of a love frequency is about singing, playing and listening to music in general, and its clearest results come from people making music in a group.

What one study looked at. In 2015 Eiluned Pearce, Jacques Launay and Robin Dunbar followed adults who had just joined weekly evening classes, 84 in singing classes and 51 in crafts or creative writing, over seven months (The ice-breaker effect: singing mediates fast social bonding, Royal Society Open Science). Before and after a class, in months 1, 3 and 7, each rated how close they felt to their group.

What it found. The singers bonded sooner. In the authors' words, "although singers and non-singers felt equally connected by timepoint 3, singers experienced much faster bonding". The other classes caught up with time.

What a review of oxytocin found. The usual explanation for music bringing people together is oxytocin, a substance the body makes that is often linked with bonding. In 2025 Chu and Tsai reviewed the research in Frontiers in Cognition: 20 studies, seven of them randomised trials, with 877 people singing, playing instruments, listening to music or in music therapy. They report that most studies found better mood or social outcomes, "but they do not always align with peripheral oxytocin (OXT) changes", and that "No significant changes in baseline peripheral OXT levels were observed after long-term interventions."

What it does not prove. None of these studies tested 528 Hz, 639 Hz or the Venus tone, and none played a single steady tone. The bonding came from doing something together, in time, as a group; the oxytocin story is mixed even for music itself.

Why it matters for listening. If a love frequency helps you feel closer to someone, the research suggests it will be because of what you do with it: listening with them, or using it as a quiet moment to think of them and then reach out. The tone is the cue, not the cause.

The US National Center for Complementary and Integrative Health sums up music research plainly:

However, because much of the research on music-based interventions is preliminary, few definite conclusions about their effects have been reached.

The guide to the science of sound healing sets out what research on sound and music has and has not found more widely.

How do you listen to the love frequencies?

Pick the one whose story means most to you and press play on its page; nothing plays until you do, and no account is needed. The Feeling disconnected? page leads with 639 Hz and offers the Venus tone beside it, with a suggestion to play one while you think of someone you would like to hear from. The 639 Hz page also has a Strings mode, with the tone quietly underneath. The 528 Hz page plays the tone most people mean, and the Venus page plays 221.23 Hz.

To hear them together, open Harmonance Studio, which plays several tones at once after a free sign-in. 639 Hz with the Venus tone blends smoothly; 528 Hz with 639 Hz has a slight edge, because the two sit close together in the ear. No study sets a length or promises a result, so listen for a few minutes and notice what you notice.

Keep the volume low. Loud listening is the one risk that is well established: the National Center for Complementary and Integrative Health notes that "listening to music at too high a volume can contribute to noise-induced hearing loss", and the World Health Organization's safe listening advice is that "you can safely listen to a sound level of 80dB for up to 40 hours a week", with your device's volume at no more than 60% of maximum.

The three belong to larger sets. The Solfeggio collection plays 528 Hz and 639 Hz beside the other seven Solfeggio tones, and the guide to the Solfeggio frequencies tells the whole set's story. The planetary collection plays Venus beside the other planets. For a pairing built from the same set, the guide to 396, 639 and 963 Hz together takes apart another trio.

Sources and limits

The history of each number rests on primary records: the Book of Numbers itself, the 1999 publisher's press release and a 2002 list of the tones, both read in the Internet Archive's copies, a catalogue record of the 2011 book, NASA's fact sheet and pages for the Venus year and the planet's name, and Cousto's own tables and text for the Venus tone. No study has tested 528 Hz, 639 Hz or 221.23 Hz on love, closeness or relationships. The research described is about making and hearing music in general, and it cannot say what any one tone does. The measurements of the three pages' sound are Harmonance's own, made from the site's audio files; the roughness and loudness figures come from models of an average ear, not from listeners.

1. The Book of Numbers, chapter 7, King James Version (eBible.org): the verses whose numbers give the Solfeggio digits.
2. Tetrahedron Publishing (1999), press release for the book that published the six tones, Internet Archive: the digit method, and 528 as the syllable MI.
3. Soma Energetics (2002), The Six Solfeggio Frequencies, Internet Archive: the early words for 528 Hz and 639 Hz.
4. Leonard G. Horowitz (2011), The Book of 528, catalogue record on Goodreads: the 2011 book that tied 528 to love.
5. NASA, Venus fact sheet: the sidereal orbit of Venus, 224.701 days.
6. Hans Cousto, tuning data for the planets: the Venus year of 224.7008 days and its 32nd octave, 221.23 Hz, an A.
7. Hans Cousto, Venus, 221.23 Hz (in German): the effect his text gives the Venus tone.
8. NASA Science, Venus facts: the planet named for the Roman goddess of love and beauty.
9. Pearce, Launay and Dunbar (2015), The ice-breaker effect: singing mediates fast social bonding, Royal Society Open Science: singing classes and closeness over seven months.
10. Chu and Tsai (2025), Music's context-dependent influence on oxytocin, social bonding, and emotion regulation: a systematic review, Frontiers in Cognition: 20 studies of music and oxytocin.
11. Plomp and Levelt (1965), Tonal consonance and critical bandwidth, Journal of the Acoustical Society of America: tones further apart than a critical band sound consonant.
12. Moore (2014), Development and current status of the Cambridge loudness models, Trends in Hearing: the ear's filter widths and the Cam scale.
13. National Center for Complementary and Integrative Health, Music and Health: What You Need To Know: the state of music research, and loud listening.
14. World Health Organization, Deafness and hearing loss: safe listening: safe levels and device volume.