What a harmonic chart is
To build harmonic N, take each body's natal longitude, optionally subtract an anchor such as your Ascendant, multiply by N, and fold back into the 0–360° circle. The result is a new wheel in which the angles between things are N times their natal size — a magnifying glass for particular separations.
The analogy to harmonics in acoustics is deliberate (the technique was systematised by Adler and popularised in the 1970s–80s): just as a vibrating string emits multiples of its fundamental, the natal chart 'emits' H2, H3, H4… each one amplifying a different family of natal angles into exactness.
How we compute it
Each placement of your natal chart, built from the VSOP87/ELP ephemeris, is mapped with the exact formula (λ − anchor) × N mod 360°, on the tropical zodiac — identical arithmetic to any professional harmonic function. The optional 'measure from my Ascendant' anchor subtracts your Ascendant first, so the harmonic Ascendant lands on 0° Aries; unanchored, the whole ring is simply stretched from 0° Aries.
The tool then counts which sign collects the most multiplied bodies and, at three or more, prints it as the harmonic's headline cluster — the reading move nearly all harmonic authors make first.
What you get
After entering one birth date, time and place, the report shows:
- A chip selector for H2, H3, H4, H5, H6, H7, H8, H9, H10 and H12, each with its traditional theme.
- Every natal body plus Ascendant and MC in the chosen harmonic, side by side with the tropical original.
- The headline cluster: which sign gathers three or more multiplied bodies, named for you.
- Element and modality tallies of the harmonic chart, plus a count of how many bodies changed sign under multiplication.
How the harmonics are traditionally read
Each harmonic is said to describe one department of life by taking the natal chart's 'fine print' to full size: H4 foundations and inner security, H5 creativity and romance, H7 partnerships and analysis, H10 status and achievement. The chart's cluster sign and the planets inside it are read as that department's underlying groove.
Because multiplication magnifies separations, a tight natal stellium typically explodes across the harmonic wheel, while planets born 30°/N apart collide into exact conjunctions — the technique rewards charts with close degrees. Treat all of it as symbolic pattern-language: the math is exact, the interpretive claims are tradition, not evidence.
A worked example: born 1 January 2000, 17:30 UTC, London
This chart's tropical Sun sits at 10.6° Capricorn (longitude 280.6°) and Moon at 16.1° Scorpio, with Cancer 28.8° rising. Multiply everything by 5, unanchored, and the fifth harmonic reads: Sun 23.0° Aquarius, Moon 20.4° Taurus, Ascendant 24.0° Scorpio — a wholly new distribution from the same birth moment.
Switch to H4 and the same numbers give Sun 12.4° Taurus, Moon 4.3° Libra, Ascendant 25.2° Cancer; at H7, Sun 14.2° Virgo, Moon 22.5° Leo, Ascendant 21.6° Cancer. Each harmonic is a different 'exposure' of one negative: the separations you can trust are the natal ones scaled up — in H5 a 7° natal gap becomes 35°, which is why bodies that seemed unrelated in the natal chart can share a harmonic sign exactly.
What this tool does not claim
Harmonic astrology is a 20th-century technique with a small literature and no controlled testing; we present its themes as tradition. The arithmetic itself is exact and matches professional software to the degree, including the anchor convention (we offer both 0° Aries and Ascendant anchoring, which differ — check which your source uses).
Harmonic charts have no independent houses or angles in our presentation: the harmonic Ascendant and MC are your natal ones multiplied like everything else, and no house cusps are claimed. All computation runs locally; your birth data never leaves your browser.
Harmonics vs the other re-charted frames
The sidereal and draconic charts subtract a constant — a rigid rotation that preserves every aspect. The harmonic chart multiplies, which destroys the natal aspect pattern on purpose to build a new one. And the heliocentric chart changes the observer instead of the arithmetic. Together the four tools on this family are a live demonstration that a 'chart' is a chosen coordinate system, not a given fact.
Our method in one line
Natal positions from sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine), multiplied by integer N with the chosen anchor, folded into the tropical ring; clusters counted, not asserted. Reviewed by Dr. Amara Osei, Astronomy Reviewer.
Step by step
- 1
Enter one birth record
Date, time and place — a harmonic chart is derived from the natal, so it needs the same inputs.
- 2
Pick a harmonic
Tap H2 through H12; the report recomputes instantly. The chips carry the tradition's shorthand: H5 creativity, H7 relationships, H10 achievement.
- 3
Try the Ascendant anchor
Tick 'measure from my Ascendant' to rotate the multiplication so your harmonic Ascendant lands exactly on 0° Aries — many books use this convention.
- 4
Read the cluster
The headline names the sign where three or more of your bodies pile up in that harmonic — the department-of-life reading starts there.
Tip — Compare two harmonics on the same chart: a body that leads one cluster and vanishes in another shows you natal angles, not planet 'identity', driving the technique.
Frequently asked questions
- What does each harmonic number mean?
- Traditionally: H2 duals and one-to-one encounters, H3 expression and social self, H4 roots and security, H5 creativity and romance, H6 work and health, H7 partnership and analysis, H8 shared power and transformation, H9 completion and long cycles, H10 career and public direction, H12 the hidden or behind-the-scenes pattern. These themes are the technique's folklore, settled by authors like Adler and Levani, not by evidence.
- Should I anchor the harmonic on my Ascendant?
- Both conventions exist and give different charts (rotated relative to each other). Anchoring on the Ascendant makes the harmonic Ascendant exactly 0° Aries, which most books prefer because it keeps an 'angle' in the new wheel. Unanchored multiplication preserves comparison to 0° Aries in the base zodiac. The tool lets you toggle and shows the anchor used.
- Why do my planets change sign so drastically in high harmonics?
- That is the point: multiplying longitude by N scales every separation by N. A body at 280.6° becomes 1403°, which folds back to 23.0° — distance travelled around the ring is essentially arbitrary after the fold, so only the deliberate amplification of specific natal angles carries meaning in the technique.
- Is there an H11 or H13?
- You can compute any integer harmonic — nothing stops H11 or H16; the named tradition simply stops caring around H12. We expose the ten best-established numbers to keep the tool tied to literature people actually recognise.
- Is my birth data private?
- Calculations run entirely in your browser. Your birth data is never uploaded, never stored on a server, and never shared. The multiplication runs locally on your natal positions; nothing is uploaded or stored.
Written by
Elena Marchetti
Founder & Staff Astrologer
Methodology reviewed by
Dr. Amara Osei
Astronomy Reviewer
Published 2026-10-01 · Updated 2026-10-01 · Calculated with sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine)