Check the inputs before interpreting a result
For a birth chart, enter the local clock time recorded at birth. Do not convert it to UTC yourself when you select a listed city: the calculator performs that conversion. For a custom location, check the offset that applied on the birth date, including daylight saving if relevant. An incorrect time zone changes the moment being calculated.
If you only know the date, select “Unknown birth time” in the birth chart calculator. Its noon estimate leaves out the Ascendant and houses. For example, an estimated Moon placement close to a sign boundary is a reason to check the recorded time, not to choose whichever interpretation feels better.
Different tools use different methods. The birth, Moon and Rising calculators use Astronomy Engine for planetary positions; that does not describe every specialized calculator in this directory. Read the method and supported range on the page you use. Numerology reductions and compatibility scores follow symbolic rules. The birth chart guide explains how to read placements once you have checked the inputs.