A natal chart calculator that generates a precise astrological birth chart using Swiss Ephemeris — the same astronomical engine used by professional astrologers worldwide. Enter your birth date, time, and location to receive a complete natal chart with planetary positions, house cusps, aspects, and in-depth analysis.
Unlike simplified horoscope apps, this tool computes exact degree positions for all major planets, the Ascendant, Midheaven, Chiron, lunar nodes, Black Moon Lilith, and the Part of Fortune. The results are rendered as a publication-quality SVG chart and can be exported as a PNG image with a labeled footer.
Core Features
- Full natal chart with all major planets, axis points, and additional bodies (Chiron, lunar nodes, Lilith, Part of Fortune)
- Detailed data tables for planetary positions, house cusps, and aspects with orb values
- Aspect analysis covering all major and minor aspects (conjunction, sextile, square, trine, opposition, and more)
- Elemental and modal balance showing the distribution of planets across Fire, Earth, Air, and Water, as well as Cardinal, Fixed, and Mutable signs
- Lunar phase at birth with moon phase name and Sun–Moon angle
- Transit overlay to compare current planetary positions against the natal chart
- Multiple zodiac systems: Tropical (Western) and Sidereal (Vedic)
- Nine house systems: Placidus, Whole Sign, Koch, Regiomontanus, Campanus, Porphyrius, Alcabitus, Morinus, and Horizontal
- Chart themes and styles: Light, Dark, Classic, High Contrast, Strawberry, and Black & White; Modern and Classic drawing styles
- PNG export with a footer indicating the tool URL and attribution
How to Use
Step 1 — Enter Birth Details
Fill in the name (optional), birth date, and birth time. If the exact birth time is unknown, enable "Birth time unknown" to calculate the chart for 12:00 noon, which is the standard convention. Note that without an accurate birth time, house cusps and the Ascendant will not be reliable.
Step 2 — Set the Birth Location
Type a city name in the search box and select a result from the dropdown. The tool uses OpenStreetMap geocoding to find coordinates automatically. Alternatively, click the GPS button to use your current location, or expand "Enter coordinates manually" to input latitude and longitude directly.
Verify the timezone field. It defaults to your browser's timezone, but you may need to enter the timezone of the birth location (e.g., America/New_York, Europe/Paris, Asia/Tokyo).
Step 3 — Configure Chart Settings
- Zodiac System: Tropical is the standard Western system; Sidereal (Vedic) shifts sign positions by approximately 23–24 degrees.
- House System: Placidus is most common in Western astrology. Whole Sign is widely used in Hellenistic and Vedic traditions. Choose the system that matches your preferred tradition.
- Chart Theme and Style: Select a visual theme and drawing style to suit your preference.
- Chart Language: The chart SVG labels (planet and sign glyphs) can be rendered in multiple languages.
- Include current transits: Overlays today's planetary positions on the natal chart wheel.
Step 4 — Generate and Explore
Click "Generate Natal Chart." The chart opens with five tabs:
| Tab | Content |
|---|---|
| Chart | The SVG natal chart wheel |
| Planets | Table of planet positions, house placements, elements, and qualities |
| Houses | Table of house cusps with signs, elements, and qualities |
| Aspects | Sortable list of all aspects with orb and applying/separating status |
| Analysis | Moon phase, elemental/modal balance, chart summary, and technical details |
Step 5 — Export PNG
Click "Export PNG" to download the chart as a high-resolution PNG image. The image includes the natal chart wheel at full resolution and a dark footer bar with the tool URL and attribution.
Parameter Notes
Timezone: Always enter the IANA timezone identifier for the birth location, not just the UTC offset. Offsets like UTC+5:30 do not account for historical daylight saving time changes, which can shift the chart by one hour or more for dates in the past.
Orb: The orb value shows how far an aspect deviates from exact. Tighter orbs (closer to 0°) represent stronger influences. Use "Major aspects only" to filter out minor aspects and focus on the five classical aspects.
Applying vs. Separating: An applying aspect means the two planets are moving toward exact alignment; a separating aspect means they are moving apart. Applying aspects are generally considered stronger.
Usage Examples
Personal birth chart — Enter your name, exact birth date and time, and the city where you were born. Select Placidus houses for a traditional Western reading. Use the Analysis tab to review your Big Three (Sun, Moon, Ascendant) and elemental balance.
Vedic chart — Switch the zodiac system to Sidereal and select Whole Sign as the house system. The planetary positions will shift to reflect the sidereal zodiac used in Jyotish astrology.
Transit comparison — Enable "Include current transits" to overlay today's positions over the natal chart. This is useful for identifying active transit periods such as Saturn returns, Jupiter conjunctions, or eclipse contacts.
Notes and Limitations
- Birth time accuracy significantly affects house cusps and the Ascendant. An error of four minutes in birth time can shift the Ascendant by approximately one degree.
- The chart is calculated entirely in the browser using WebAssembly. No birth data is sent to any server.
- City search requires an internet connection (OpenStreetMap Nominatim). Manual coordinate entry works offline.
- The Sidereal calculation uses the Lahiri ayanamsa by default, which is the standard in Jyotish. Other ayanamsas are not currently configurable.