# House Systems Comparison Calculator
> Compare the same birth chart across Placidus, Koch, Equal, Regiomontanus, and Whole Sign where supported.
## Tool Metadata
- Slug: house-systems-comparison-calculator
- Published: 2026-10-14T01:33:28.722075+00:00
- Last Updated: 2026-10-14T02:04:28.928949+00:00
- Reading Time: 1 min
- Word Count: 144
## Related links
- [House Systems Comparison Calculator](https://www.yesastrology.com/en/tools/chart-calculators/house-systems-comparison-calculator)
- [Canonical URL](https://www.yesastrology.com/en/tools/chart-calculators/house-systems-comparison-calculator)
- [Page LLMS URL](https://www.yesastrology.com/en/tools/chart-calculators/house-systems-comparison-calculator/llms.txt)
See which houses change across house systems and which placements remain consistent.

See which houses change across house systems and which placements remain consistent.

## How it works

The calculator holds birth date, local time, time zone, and coordinates fixed, then compares supported house assignments for the Sun, Moon, planets, and Chiron. It records when a method is unavailable at high or polar latitudes and when the upstream chart calculation uses a Porphyry fallback. Zodiac degrees are not changed by this comparison. Placidus is the reference for identifying changed house numbers when it is supported.

## Interpretation and limits

Compare the same birth chart across Placidus, Koch, Equal, Regiomontanus, and Whole Sign where supported. Results describe astrological calculations and should be read with the stated inputs, selected method, and practical context.
## Frequently asked questions
### Why do house placements change between systems?

House systems divide the sky using different mathematical rules, so a planet near a cusp can fall in different houses while its zodiac position stays the same.

### Which house system is correct?

Astrologers use multiple house systems. A comparison shows their differences without declaring one universally correct.
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