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Birth-time uncertainty explorer

Compare a recorded birth-time interval and see which signs and house placements change. No guessed birth time or personality-based rectification.

A time written as “around seven” should not become an invented exact minute. Enter a plausible interval and inspect how the chart changes across it. The result separates positions that are unchanged at the checked instants from those with more than one possible sign or house.

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Birth details

Birth dateRecorded local birth time

IANA time zone

Use the place’s time zone, such as Europe/Warsaw or America/Sao_Paulo. Keep the recorded clock time; do not adjust for summer time yourself.

If the clock time occurred twice

One fixed download; the selected country or city is never sent in a request.

Birthplace latitudeBirthplace longitude

House system

End of the interval, on the same local dateIf the end clock time occurred twice

Place data: GeoNames geographical database,CC BY 4.0. Snapshot retrieved 27 August 2026. The cities15000 directory does not include every settlement; manual coordinates and time zones remain available.

No name, email or account is needed. Your details stay on your device. Use the clear button to remove entered details and results.

How to use this tool

Enter the beginning of the interval as the birth time and supply the end on the same local date. Use the birthplace time zone. If clocks repeated, choose the occurrence separately for the start and end. A local date can be shorter or longer than 24 hours. This tool does not reconstruct a missing record or assign probabilities to the minutes.

How to read the result

Read the sign and house tables separately: a planet may remain in one sign while its house changes. The Ascendant can change more quickly than the planetary positions. Gradual sign crossings are refined between samples. Large jumps remain unresolved brackets, without an invented exact crossing or intermediate signs. The two-minute grid is not a mathematical guarantee between every sample.

Method and limits

This is a sensitivity analysis, not birth-time rectification. It cannot tell you which minute is correct from life events, appearance or personality. The same ephemeris, polar-house and historical time-zone limitations as the full chart apply. Consult the original record when possible.

The calculation uses Astronomy Engine 2.1.19 and, where applicable, the project’s offline time-scale and house geometry modules. Mathematical positions and traditional interpretation remain separate.Read the full methodology.