Human Design guide · Reviewed October 13, 2026

Why do two Human Design charts disagree?

When two charts disagree, start with the inputs rather than deciding that one provider is wrong. A single changed date, time, or time-zone assumption can move planetary positions across the boundaries used to assign gates and lines. Different calculations can also produce differences even when the typed text looks identical.

Compare the same information in both forms

1. Check the calendar date and its format. May 14 is not the same as a date interpreted in day/month order.
2. Select the actual birthplace, not your current city or another town with the same name. Compare the selected country and time zone.
3. Enter the recorded local clock time, including AM or PM. Do not convert to UTC yourself unless a form specifically asks for UTC.
4. Use the same known-time or unknown-time setting. An unknown-time noon anchor is not interchangeable with a recorded noon birth.

Our reproducible input

Fictional Jordan's May 14, 1991, 7:40 AM in America/Denver resolves to 1991-05-14T13:40:00.000Z. The offset used is -360 minutes east of UTC. The resolver flags are ambiguous: false, nonexistent: false, local mean time: false. Our birthToUtc wrapper returns this same instant. The design-date guide explains the second calculation instant.

Daylight saving is not a universal one-hour correction

Our resolver uses Luxon with the runtime's ICU time-zone data. On a repeated clock time it chooses the earlier instant and provides a later alternative. For example, London October 31, 2021 at 1:30 AM resolves to 2021-10-31T00:30:00.000Z, with alternative 2021-10-31T01:30:00.000Z. On a nonexistent clock time during a forward change, it uses the pre-change offset, effectively moving the time forward by the gap. This is a software convention, not proof of which time a record intended.

Historical data can be incomplete, especially before 1970 or where local practice differed from a zone's reference city. Our resolver can use birthplace longitude for local mean time before standard time, but this does not remove all historical uncertainty. Ask for help with an ambiguous record rather than automatically subtracting an hour.

Then compare methods

Born Blueprint uses apparent planetary positions, the true lunar node, and a design moment based on an 88-degree solar arc. Another provider may use different conventions or time-zone data. Record the settings before comparing labels. A disagreement alone cannot establish which tool is correct, and matching charts do not scientifically validate personality claims. If your birth time is missing, read our sampling limits before making a comparison.

Sources and further reading

The Jovian Archive FAQ describes the tradition and the importance of birth details. Its Authority introduction explains the traditional terminology. These are descriptions of the system, not independent validation of its claims.

IANA's time-zone database documents historical local-time rules. NASA JPL Horizons provides astronomical ephemerides; it does not validate Human Design. DefinedSelf's published measurements concern its own methods and samples. We do not treat its stability percentages as measurements of Born Blueprint.

Explore your own free chart

Make your free chart. The form asks for your name and birth details. No email is needed to see your chart. The chart comes first; a $37 reading is optional. Check any uncertainty before considering a paid reading.