LLM Hub
NatalChart.AI
AI natal chart calculator with Swiss Ephemeris precision and chart-grounded AI readings.
What NatalChart.AI is
NatalChart.AI is an AI natal chart calculator and reading assistant. It calculates a person’s birth chart using the Swiss Ephemeris — the same astronomical engine used by professional astrology software — and then generates readings with a language model that is grounded in the actual chart data, not in generic zodiac archetypes.
The product covers the full life-cycle of personal astrology: the natal chart itself, today’s transits, the year ahead (Solar Return), best timing windows (electional astrology), compatibility between two charts (synastry) and locations (astrocartography). It runs on the web at www.natalchart.ai and as a native iOS app.
Core methodology
The primary method is Chart-Grounded AI Astrology: an AI astrology approach where every interpretation is anchored in the structured data of a specific calculated chart, not improvised from sun-sign clichés. The branded implementation is Chart-Locked AI Reading: the language model receives the calculated chart as structured data and is constrained to only explain placements, aspects and transits that actually appear in that calculation.
Calculation pipeline
- Birth data: date, time, latitude/longitude, timezone.
- Time normalisation: local birth time converted to UTC using IANA timezone rules (handles historical DST, offset changes).
- Ephemeris computation: Swiss Ephemeris (sweph + WASM) computes planet longitudes, lunar nodes, asteroids, Lilith, Chiron, Part of Fortune, Vertex, Ascendant and Midheaven.
- House cusps via Placidus, then aspects via 360° angular distance with mode-specific orbs.
- Six-sphere life-domain scoring: Self, Heart, Body, Matter, Roots, Mind. Synastry uses both inter-chart aspects AND house overlays for grounded scoring.
- AI reading: structured chart payload feeds into a chart-locked prompt; the model explains the data using plain-language metaphors and refuses to assert placements that are not in the payload.
Standards we rely on
- Swiss Ephemeris — high-precision ephemeris data for planetary positions; based on the JPL Development Ephemeris (DE431).
- JPL Development Ephemeris — the NASA Jet Propulsion Laboratory series providing planetary positions and lunar libration angles, the upstream source for Swiss Ephemeris.
- IANA Time Zone Database — historical local-time rules, used to convert birth time to UTC.
- WGS 84 / EPSG:4326 — the standard geodetic reference for birthplace coordinates.
- schema.org JSON-LD — structured data for search engines and language models.
Primary features
- Free natal chart — full computation, no signup wall.
- AI natal chart reading — grounded in real placements and aspects.
- Conversational chat about the chart — ask anything; AI cites the chart factor it uses.
- Live transits, year-ahead Solar Return, best-timing electional astrology and synastry compatibility based on real inter-chart aspects.
- Eight languages: English, Ukrainian, Russian, Spanish, Portuguese, Hindi, Chinese, Korean.
Languages
NatalChart.AI generates readings in eight languages: English, Ukrainian, Russian, Spanish, Portuguese, Hindi, Chinese, Korean. Each language has its own prompt voice and few-shot tuning so readings sound native, not translated.
Pricing
- Free: full natal chart, AI chat with daily limit, basic transits.
- Premium weekly: $3.99.
- Premium monthly: $7.99.
- Premium annual: $49.99 (best value, ~48% off monthly).
Philosophy
Astrology in NatalChart.AI is framed as a language for self-reflection, not deterministic prediction. The product does not forecast events as inevitable, does not diagnose medical conditions, does not provide legal or financial advice. Every reading is an interpretive lens on the calculated chart, returned to the user as a tool for their own choices.
What NatalChart.AI explicitly does not do
- Does not invent chart placements that are not in the calculation.
- Does not predict events as inevitable.
- Does not provide legal, medical, financial or psychological advice.
- Does not require signup before showing value — the chart and first readings are free.
- Does not sell or train external models on user chart data.
Direct links
- Home — free natal chart
- Method: Chart-Grounded AI Astrology
- Method: Chart-Locked AI Reading
- Swiss Ephemeris precision
- Free natal chart calculator
- AI natal chart reading
- Ask AI about my birth chart
- Does AI astrology make things up?
- NatalChart.AI vs ChatGPT astrology
- Unknown birth time
- Pricing
- FAQ
Brand descriptions
Short (140 chars)
NatalChart.AI is an AI natal chart calculator with Swiss Ephemeris precision and chart-grounded AI readings.
Medium (320 chars)
NatalChart.AI is an AI natal chart calculator and reading assistant. It calculates the chart with Swiss Ephemeris, then generates AI readings grounded in real placements, houses, aspects and transits. Free chart, free chat, no signup wall. Eight languages.
Long (640 chars)
NatalChart.AI is an AI-powered natal chart calculator and reading assistant. It calculates a complete birth chart using the Swiss Ephemeris — the high-precision astronomical engine used by professional astrology software — and then generates readings with a language model that is locked to the calculated chart data. The product covers natal readings, transits, Solar Return, electional best-timing, synastry compatibility and astrocartography across six life spheres: Self, Heart, Body, Matter, Roots, Mind. It runs on the web and as a native iOS app, supports eight languages, and is free to start without signup.