Calculate the chart before interpreting it
GetBirthChart's free layer includes a natal wheel, planetary placements, houses, aspects, balance summaries, Today's Sky transits, a year-ahead preview, and three AI questions. The form accepts a birth date, time, and place, then sends the normalized time and coordinates to a dedicated calculation engine. Tropical zodiac with Placidus houses is the default, while Whole Sign and Equal houses can be selected in the advanced settings.
The result keeps calculation and interpretation separate. Planetary positions come from Swiss Ephemeris through the open-source gbc-astro Python engine. Local time is resolved through the IANA timezone database, and every chart records the engine, ephemeris, and timezone-data versions used to produce it.
Unknown birth time stays unknown
If the exact time is unavailable, GetBirthChart does not silently substitute midnight or noon. Rising sign, houses, and chart angles are omitted. Most planetary signs remain available, while the Moon is marked as time-dependent when it crosses a sign during that local date. The public methodology also documents aspect orbs, high-latitude Placidus limits, daylight-saving boundaries, and regression cases.
Synastry, yearly timing, and chart-grounded questions
The compatibility tool compares two full charts through cross-chart aspects, house overlays, and a composite rather than relying on Sun signs alone. The yearly view combines annual transits with a Solar Return. Both begin with a free preview.
AI interpretation sits after the calculation. The model receives selected structured chart evidence rather than inventing placements, and the published architecture excludes the chart UUID, email, coordinates, place label, and date of birth from the reading payload. A full natal reading is $9.99 and a couple reading is $14.99, both one-time purchases; additional question packs are also sold once rather than as subscriptions. Charts are private by default, an account is optional for the basic calculators, and the privacy policy says birth data is not sold.
