Birth chart calculator comparisons

Start with the test method

The comparison methodology explains how settings are matched, how displayed longitudes are normalized, how differences are classified, and how unknown birth time is handled. It also separates direct observations from claims that require more evidence.

Why results differ

The guide Why birth chart calculators give different results walks through a reproducible Tropical, Placidus fixture: planetary placements, angles, all twelve house cusps, lunar nodes, aspects and an unknown-time run.

A product comparison

The balanced GetBirthChart vs Astro-Seek comparison records the observed calculation and interface differences without declaring a universal winner. Use it to choose the surface that fits your current need, then verify any important result with matched settings.

The new GetBirthChart vs Cafe Astrology comparison and GetBirthChart vs Astro-Charts comparison use the same synthetic fixture and updated True North Node / Chiron behavior. They separate calculation agreement from workflow, customization, report and privacy differences.

Focused calculation questions

True Node vs Mean Node explains the most visible North Node degree difference and shows how to disclose the node mode. Birth chart without an exact birth time maps which facts remain available, how noon references work, and what a calculator should omit rather than guess.

The evidence boundary

The current cluster uses one synthetic fixture, one captured test date and the outputs recorded in the comparison files. It is useful for transparency and replication, not a claim about every date, location, setting or calculator version. Product behavior and source pages can change, so comparison pages include their test date and correction path.