How to find your birth time.

Why it matters

The whole chart rotates.

Your birth date sets where the planets were. Your birth time sets where they were relative to the horizon you were born under, and that is what produces the rising sign and the twelve houses. The houses are what turn a description of temperament into a description of your life: which part of it a placement shows up in.

The Moon moves roughly half a degree an hour, so a few hours of error can move it into a different sign entirely. The rising sign changes about every two hours. An unknown birth time does not make a chart useless, but it makes about a third of it guesswork, and I would rather tell you which third than quietly average it out.

Where to look

In rough order of reliability.

1. Your long-form birth certificateNot the wallet card. The long-form or "vault" copy is the one that carries the hour of birth. In the United States you order it from the vital records office of the state where you were born, usually for fifteen to thirty dollars, and it takes anywhere from a few days to a few weeks.
2. Hospital recordsIf the certificate does not show a time, the hospital that delivered you may still hold the record. Ask for the medical records department, and be prepared for them to have nothing that old.
3. A baby book or announcementParents who wrote it down usually wrote it down within a day, and printed birth announcements often carried the time.
4. Family memory, used carefully"Just before dinner" is worth having. "Around noon" is worth having. What is not worth having is a remembered time that has been rounded to the hour, then repeated for thirty years until it sounds precise. If it is approximate, tell me it is approximate.

If you never find it

What still works.

• Chinese astrology gives you three of four pillars without a birth time, and the reading holds up.
• A birth chart reading still works for planets in signs and for aspects. I read it without houses and say so, rather than presenting a rising sign I invented.
• Transits to those same placements still work.
• A psychic reading needs no birth data at all.
• Human Design is the one to avoid. It is minute-sensitive enough that a wrong time can produce a confidently wrong type, which is worse than no reading.

On rectification

Something I do not offer.

There is a technique called rectification that works backwards from events in your life to estimate an unknown birth time. Practitioners who specialise in it spend hours on a single chart. I do not offer it, and I would rather point you at someone who does than approximate it badly.

More on the practice