From ancient Whole Sign to modern Placidus.
All major house division methods with Swiss Ephemeris precision in <300ms.
The House Systems API works best combined with our other tools. Add
Built for scale, optimized for speed
From ancient methods to modern cutting-edge calculations
Everything astrology software needs to support all major house calculation methods
Ever wonder why your birth chart looks different on Co-Star versus Cafe Astrology? It's because they use different house systems to divide your chart into 12 houses. Think of it like different ways to cut a pizza - same ingredients, different slices. Our House Systems API supports 23+ calculation methods, from ancient Whole Sign (used for 2000+ years) to modern Placidus (what most use today). Professional astrologers need options because different house systems reveal different layers of information. We calculate them all with Swiss Ephemeris precision in under 300ms. It's like having all major astrology software's house calculation engines in one API. Our implementation follows Swiss Ephemeris documentation for houses - Placidus, Koch, Whole Sign, Equal, and 19+ more systems calculated with the same accuracy you'd find in professional desktop software.
Here's the thing: house systems determine WHERE planets fall in your chart, which changes everything.
In Placidus houses, your Mars might be in the 7th house of relationships.
Switch to Whole Sign, and suddenly it's in the 8th house of transformation.
Same planet, different meaning.
Professional astrologers use multiple systems because: (1) Ancient techniques work better with traditional houses, (2) Modern psychology fits better with modern systems, (3) Different systems highlight different life themes.
It's like having multiple camera lenses - wide angle shows the big picture, zoom lens shows details.
Our API calculates all 23+ systems instantly so your users can explore different perspectives on their chart.
Placidus is what most know - houses have different sizes based on birth location and time.
If you're born in Alaska, your houses look stretched compared to someone born in Florida.
It's mathematically complex but feels "personal" because it uses your exact coordinates.
Whole Sign is simpler - each house is exactly 30 degrees, starting with your rising sign.
Ancient astrologers used it because it's clean and consistent.
Modern research shows Whole Sign works better for timing techniques and life periods, while Placidus excels in psychological analysis.
Professional software needs both.
Our API switches between them instantly so astrologers can compare interpretations side by side.
Integration is surprisingly simple - one API call returns all house systems simultaneously.
Send birth data, get house cusp positions for Placidus, Equal, Whole Sign, Koch, Regiomontanus, Campanus, and 17+ more.
Most developers implement it as a dropdown menu: "View in: Placidus | Whole Sign | Equal" etc.
Advanced users love this flexibility.
Implementation takes about 30 minutes: (1) One API call fetches all systems, (2) Frontend switches between them, (3) UI updates house positions automatically.
We handle all complex calculations - great circles, oblique ascension, prime vertical calculations.
You just choose which system to display.
Different astrological traditions use different house systems, and professionals need to speak all languages.
Hellenistic astrology requires Whole Sign houses.
Medieval techniques work best with Regiomontanus.
Vedic astrology uses Equal houses.
Modern psychological astrology prefers Placidus.
It's like being a translator - you need to understand multiple dialects of the same language.
Also, research shows different systems excel at different prediction methods.
Whole Sign is better for annual profections.
Placidus works great for progressions.
Equal houses shine in electional astrology.
Our API serves the professional market where accuracy and tradition matter.
House system calculations are pure math - there's no room for interpretation, only precision.
We use Swiss Ephemeris data (same as NASA JPL) with 0.001° accuracy.
This means if we calculate your Medium Coeli at 15°23'45" Gemini, it's mathematically correct to the arc second.
Why does this matter? Because house cusps determine planet placement.
Being even 30 arc minutes off could put a planet in the completely wrong house.
Some free calculators use simplified math and can be off by several degrees.
Professional astrologers can't afford that kind of error.
Our calculations match exactly with SOTA astrology software like Solar Fire, Kepler, and Sirius.
Each house system shines in specific contexts.
Whole Sign dominates ancient techniques: profections, zodiacal releasing, Hellenistic timing methods.
The math is cleaner and results more consistent.
Equal houses excel in horary (question astrology) and electional work because they treat all houses equally.
Placidus works best for psychological analysis and modern transit work because the unequal houses mirror life's natural imbalances.
Koch (birthplace) handles extreme latitudes better than Placidus.
Topocentric claims greater astronomical accuracy.
Professional astrologers choose systems based on technique, not personal preference.
Our API supports this flexibility by calculating everything simultaneously.
Comprehensive house system support for desktop applications like Solar Fire and Kepler
Multiple house system options for serious astrology apps and chart calculators
Teaching tools that demonstrate how different house systems affect interpretation
Professional tools for astrologers working with multiple house systems
Academic tools to study house system effectiveness in different techniques
Forums and social platforms where users compare charts in different house systems
| Total House Systems | 23+ traditional and modern calculation methods |
| API Response Time | <300ms for all systems simultaneously |
| Mathematical Precision | 0.001° accuracy with Swiss Ephemeris |
| Supported Systems | Placidus, Whole Sign, Equal, Koch, Regiomontanus, Campanus, Topocentric |
| Ancient Methods | Whole Sign, Equal, Porphyry, Alcabitius |
| Modern Systems | Placidus, Koch, Topocentric, Meridian, Vehlow |
| Specialized Systems | Gauquelin, Solar, Lunar, Morinus |
| Extreme Latitudes | All systems handle polar regions correctly |
| Timezone Support | Global coverage with historical DST data |
| Date Range | Coverage from 13,000 BCE to 17,000 CE |
| Output Format | JSON with exact house cusp degrees for all systems |
| Batch Processing | Calculate multiple charts with all house systems |
| Validation | Cross-checked with major astrology software |
| Documentation | Complete mathematical formulas and references |
| SDK Support | JavaScript, Python, PHP, Ruby libraries available |
| Feature | Astrology API | Others |
|---|---|---|
| Number of House Systems | 23+ systems | 3-8 systems |
| Response Time | <300ms all systems | 500-2000ms per system |
| Mathematical Accuracy | 0.001° precision | 0.01-1° precision |
| Ancient Systems | Complete support | Limited or missing |
| Extreme Latitudes | All systems work | Some systems fail |
| Batch Calculation | All systems at once | One system per call |
| Documentation | Mathematical formulas | Basic descriptions |
| Professional Features | Research-grade tools | Consumer-oriented |
| Price | $11-37/month | $49-299/month |
| Free Plan | 100 calculations | 100-250 calculations |
| Setup Complexity | 15 minutes | 1-4 hours |
| Support Quality | Astrology experts | General developers |
Complete chart calculations with house placement
Ancient techniques that work with classical house systems
Essential and accidental dignities based on house placement
House-based aspect analysis and interpretation
Visual chart generation with multiple house system options
Complete technical reference and mathematical formulas
Start free, scale as you grow. No hidden fees, no surprises.
For small apps and personal projects
For growing apps and medium traffic
For enterprise-scale applications
All plans include comprehensive documentation and SDKs
Questions? Talk to our team
Real answers for professional astrologers and developers