Why do birth chart calculators give different results?

Check the date, local birth time, selected city, and time zone. Daylight-saving handling and historical time rules can change the UTC instant used for the chart. A one-hour difference is not a difference in interpretation.

Use identical inputs where possible and record any uncertainty. Do not assume that every discrepancy comes from one calculator being wrong.

A planet can retain its longitude while appearing in a different house under a different house system. Equal houses start at the Ascendant and advance by 30 degrees. Other methods construct cusps differently.

Astral Meridian uses equal houses. Comparing its houses with Placidus or whole-sign houses without naming that difference can make two compatible calculations look contradictory.

Tropical and sidereal zodiacs use different reference points. Confirm the zodiac convention before comparing sign labels. The reading should identify the convention it uses rather than treating the labels as interchangeable.

A printed degree may be rounded while another calculator shows minutes. A near-boundary display deserves more care than an isolated rounded number.

Astral Meridian calculates planetary positions with Astronomy Engine and applies its own equal-house and angle logic. It limits the angle calculation to 66 degrees north or south. High-latitude angles are approximate.

This method description is not a claim that every input has been independently validated against another calculator. For a useful comparison, record the input instant, method, and exact point that differs.