Our numerology methodology

Primary system: Pythagorean 3-cycle method

For all birth-date calculations — primarily the life path number — Numology uses the Pythagorean 3-cycle method, the most widely used approach in Western numerology and the standard taught in books such as The Complete Book of Numerology by David A. Phillips and Numerology and the Divine Triangle by Faith Javane and Dusty Bunker.

The 3-cycle method reduces the month, day, and year of birth separately before adding them together. This preserves master numbers (11, 22, 33) that would otherwise be reduced away if you simply added all digits at once.

Step-by-step: life path number example

For someone born on February 27, 1976:

1. Month: 2 → already a single digit → 2
2. Day: 27 → 2 + 7 = 9
3. Year: 1976 → 1 + 9 + 7 + 6 = 23 → 2 + 3 = 5
4. Sum: 2 + 9 + 5 = 16 → 1 + 6 = 7
5. Result: Life Path 7 (with Karmic Debt 16, displayed as 16/7)

Master numbers

Master numbers — 11, 22, and 33 — are never reduced further during any intermediate step. If a month, day, or year reduces to 11, 22, or 33, that value is carried forward as-is before the final addition.

Karmic debt numbers

The numbers 13, 14, 16, and 19 are karmic debt numbers in the tradition of Hans Decoz and Matthew Oliver Goodwin. When one appears in the reduction chain, we display it alongside the final digit (e.g., 16/7) to indicate its presence.

Name-based numbers: Pythagorean system

For destiny, soul urge, and personality numbers the default system is Pythagorean. Letters A–Z are assigned values 1–9 in sequence:

• Destiny: all letters in your full birth name
• Soul Urge / Heart's desire: vowels only (A, E, I, O, U, and Y)
• Personality: consonants only

Chaldean system

The Chaldean system originates in ancient Babylon. Notably, the number 9 is considered sacred and is not assigned to any letter. Switch between systems using the toggle on any name-based calculator.

Address numerology

The address number is calculated by extracting all digits from the street address, summing them, and reducing to a single digit (or master number) using the same reduceWithChain function used for all other calculations. Only the numeric characters in the address are used — letters and symbols are ignored.

Angel number (birth-date method)

We calculate the angel number by formatting the birth date as MMDDYYYY, summing every individual digit, and reducing with the standard chain. This differs from the life path calculation (which preserves 3-cycle reduction) by treating every digit with equal weight. Master numbers are not preserved in this calculation — the result is always a single digit between 1 and 9.

This is distinct from repeating number sequences such as 111, 222, 333, 444, 555, 666, 777, 888, 999, 1111, and similar patterns. Those sequences are noticed in everyday life — on clocks, receipts, or number plates — and are interpreted as synchronistic messages. The birth-date angel number is a fixed value derived once from your date of birth. The two traditions share the name "angel numbers" but use entirely different methods and contexts.

Moon phase

The moon phase is calculated astronomically using the SunCalc library, which models the synodic lunar cycle (≈ 29.53 days) using standard celestial mechanics. For any given date, SunCalc returns the moon's illumination fraction (0–1) and its phase angle within the cycle (0 = new moon → 0.25 = first quarter → 0.5 = full moon → 0.75 = last quarter → 1 = new moon again). This value maps to one of eight named phases: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent. Calculations use noon UTC on the target date to avoid day-boundary edge cases. No external APIs are used — everything runs in your browser.

Moon match compatibility compares the circular phase distance between two birth moons. A score of 100% means identical phases; 0% means exact opposites (new vs. full). Neither is objectively better — both dynamics describe different relationship energies.

Personal year, month, and day

Personal year is calculated using your birth month and day along with the current calendar year. Personal month adds the calendar month to the personal year number. Personal day adds the calendar day to the personal month.

Compatibility

Compatibility scores compare two life path numbers using a matrix derived from numerological literature. Scores reflect harmonic and tension relationships — not predictions of relationship outcomes.

A note on variation across traditions

Numerology has no single canonical authority. Our choices align with the most widely adopted conventions among contemporary Western practitioners. If you notice a discrepancy, it is likely due to system differences (Pythagorean vs. Chaldean), master number handling, or Y-as-vowel treatment — all documented in the step-by-step calculation output.