Your birth chart
Don't Know Your Birth Time? How to Find It, and What You Can Still Read
Without a birth time you can still read most of your chart: the signs of the Sun and planets, and your Moon sign on more than half of all days. What you lose is the rising sign, the houses and the Lots. Here is how to find your time in the US, and what to do if you can't.
Check what your birth day can tell you without a time →
Roman OleksandrHellenistic astrologer · free checker · 10 min read
Do you need your birth time for a birth chart?
For part of it. The date alone gives you the signs of the Sun and the planets, and usually the Moon. The time gives you everything that turns with the Earth in a day: the rising sign, the twelve houses, the Midheaven and the Lots. In the old method, that second half is where a reading begins.
So a chart without a time is not useless. It is a chart without its frame. You can see what the planets are like, but not where in your life each one does its work. The rest of this page goes through both halves, then through every way I know to find a lost birth time.
What can you read without a birth time?
Your Sun sign, the signs of Mercury, Venus, Mars, Jupiter and Saturn, the slow outer planets, most of the aspects between them, and your Moon sign on most days. On about 87% of days, no planet but the Moon changes sign. The Moon changes sign on about 44% of days, so check yours below.
If your Moon changed sign that day, the checker gives the clock time of the change. Even a rough memory, "in the morning" or "just after dinner," is often enough to settle it. Aspects are mostly safe too, with one exception: the Moon moves about half a degree an hour, so an aspect to the Moon can form or fall apart within the day.
Two more things come with the date alone: the Moon phase you were born under and the weekday, with its planetary ruler.
What can't you read without a birth time?
The rising sign, and everything built on it. At San Diego's latitude the rising sign changes every 1 hour 21 minutes to 2 hours 23 minutes, depending on the sign. Without it there are no houses, no Midheaven, no Lot of Fortune or Spirit, and no clear answer to whether you were born by day or by night.
| Part of the chart | How fast it changes | Date enough? |
|---|---|---|
| Sun sign | About once a month | Yes, except on about 12 days a year |
| Mercury, Venus, Mars signs | Every few weeks to a few months | Almost always |
| Jupiter, Saturn signs | About once a year, or every two and a half years | Yes |
| Moon sign | About every 2 and a quarter days | On about 56% of days |
| Moon's degree | About half a degree an hour | Roughly |
| Rising sign | Every 1 to 2 and a half hours | No |
| Rising degree, Midheaven, Lots | About a degree every 4 minutes | No |
That loss is bigger than it sounds, because so much of the old method hangs on it. The houses say where in your life a planet acts: work, home, marriage, money. The Lot of Fortune is counted from the rising sign and moves about a degree every four minutes. Your profection year counts from the rising sign too. And whether the Sun was above or below the horizon decides your chart's sect, which changes how every planet behaves.
The farther north you were born, the more uneven the rising signs get. In New York, Aries and Pisces rise in about 1 hour 11 minutes, while Leo, Virgo, Libra and Scorpio each take about 2 and a half hours.
Why did the old astrologers care so much about the hour?
Because their whole method starts there. The Greek name for the rising sign, horoskopos, means "hour-marker," and it gave us the word horoscope. Ptolemy opens his chapter on the rising degree with the problem itself: "Difficulty often arises with regard to the first and most important fact, that is, the fraction of the hour of the birth."
He knew why. Only a horoscopic astrolabe could give the minute, he says, while sundials and water clocks, the instruments "the majority of the more careful practitioners rely" on, often erred. He lists how each fails: sundials when their positions or pointers shift, and water clocks "by stoppages and irregularities in the flow of the water from different causes and by mere chance" (Tetrabiblos III.2, tr. F. E. Robbins, at LacusCurtius). His remedy was a rule for correcting the rising degree from the New or Full Moon before the birth: an early form of rectification.
Vettius Valens gives a whole chapter of methods for finding the rising sign, some from the hour, some from the Sun and Moon alone, and promises that "for whatever hour you observe, night or day, you will find the Ascending sign" (Anthology I.4, tr. Mark T. Riley, at Skyscript). The old astrologers did not skip the hour when it was hard to get. They worked out ways to recover it.
How can I find my birth time?
Start with the record made at the time. In the US that is your birth certificate, ideally the long form, from the vital records office of the state where you were born. The CDC keeps a list of every state's office with how to order. After that come hospital records, baby books, and family.
In order of reliability:
- The long-form birth certificate. Order it from your birth state. The federal government does not issue birth certificates; the vital records office of the state, or New York City, where you were born does.
- Hospital records. If the hospital still holds records that old, ask its medical records department. Under HIPAA you have the right, with few exceptions, to inspect and get a copy of your own medical records.
- Family papers. A baby book, a family Bible, a birth announcement or a hospital bracelet often has the time written down. Astro-Databank rates a baby book or family Bible as highly as a birth certificate.
- Family memory. A parent's memory is often right, especially when it comes with a detail: "the news was on," "your father had just left for work." A bare round number, "six o'clock" or "midnight," is weaker.
Write down where each answer came from. If two sources disagree, the written record made on the day usually wins over memory.
Does a birth certificate show the time of birth?
Often, but not every certificate shows it. The current US standard birth certificate, revised in 2003, has a "time of birth" field as item 2. Older certificates and short-form copies may leave it out, so ask the state office for the long form, sometimes called the full or original copy.
The rules differ by state. Missouri, for example, says its long form "contains additional general information about the birth or death such as a time of birth or death if available" (Missouri vital records FAQ). Minnesota does not issue a long form at all, and notes that certificates for births before 2001 may not show every item, including the time; for those births an informational noncertified record, or an image of the original paper record, may show more (Minnesota Department of Health). The standard form itself is on the CDC site.
One practical note: the time on the certificate is local clock time. Clocks were often on daylight saving time, and from February 9, 1942 to September 30, 1945 the whole country was on year-round "War Time" (Wikipedia). Give an astrologer the time exactly as written; converting it is our job.
What is a noon chart?
A noon chart is a birth chart cast for 12:00 noon on your birth date, used when the time is unknown. Noon sits in the middle of the day, so no planet's position can be off by more than half a day's motion. The Moon, the fastest, is at most about 7 or 8 degrees from its true place.
A noon chart is a fair way to see the planets in their signs. It is not a way to see houses. The rising sign shown on a noon chart is simply what was rising at noon, and it has nothing to do with you. Some astrologers prefer a sunrise chart, with the Sun placed on the rising degree, which at least uses your own Sun as the starting point. Either way, read the signs and leave the houses alone.
What is birth time rectification?
Rectification is working backward from the events of a life to the birth time that best fits them. The astrologer tests candidate times against dated events, such as a marriage, a move or a new job, and keeps the time whose chart lights up on those dates. It can narrow a rough time, but it is never a certainty.
Astro-Databank, the best-known collection of birth data, rates rectified times C, for caution, at best, and says plainly that "there is no consensus on how to rectify birth times" (Rodden Rating help page). Two careful astrologers can land on different minutes.
Keanu Reeves is a good example. His time in Astro-Databank, 05:41, was rectified from his reported remark that he has Virgo rising; another astrologer rectified it to 5:18. Both give Virgo rising, but the degrees differ, so in his birth chart article I treat everything that depends on the minute as a reading of the reported time, not as fact.
My view: rectification is worth doing when you have a rough window, "between 4 and 6 in the morning," and a handful of clearly dated events. Without any window at all, it is closer to a guess. Anyone who rectifies your chart should tell you how confident they are, and why.
I do this as a separate service, Birth Time Rectification: you send your window and 8 to 12 dated events, and I send back the best-fit time, the runner-up, and how sure I am.
How exact does a birth time need to be?
For the rising sign and whole-sign houses, within about half an hour is usually enough, unless you were born near a sign change. For the exact rising degree, the Midheaven and the Lots, you want the minute: the rising degree moves about one degree every four minutes, faster or slower by sign.
Because I read whole-sign houses, as the Hellenistic astrologers did, the sign that was rising matters more than its exact degree. A time that is off by fifteen minutes rarely changes the reading. A time that is off by two hours changes almost all of it.
If your time is rounded, "around 3," or from memory, say so when you order any reading. A careful astrologer checks how close you are to a change of rising sign before writing anything that depends on it.
What do the Rodden ratings mean?
They are the grades astrologers use for how reliable birth data is, created by Lois Rodden and used by Astro-Databank. AA means from a birth certificate or birth record; A, from memory; B, from a biography; C, caution or rectified; DD, conflicting sources; X, no time; XX, no confirmed date.
| Rating | Where the time comes from |
|---|---|
| AA | Birth certificate or birth record, or the family's written record: baptismal certificate, family Bible, baby book. |
| A | The person, a relative or a friend, from memory. |
| B | A biography. |
| C | Caution: no original source, or a rectified time. |
| DD | "Dirty data": two or more conflicting times. |
| X | No time of birth known. |
| XX | No known or confirmed date of birth. |
Your own chart deserves the same honesty. If your time comes from your mother's memory, it is an A. That is usually good enough, but it is worth knowing which parts of a reading lean on it.
What can I do if I never find my birth time?
Read what is certain, and use methods that don't need the time. Your Sun, Moon on most days, and the planets in their signs still say a great deal. And horary astrology, one of the oldest branches, casts the chart for the moment a question is asked, not for your birth, so it works with no birth time.
That is why, for someone with no birth time and one pressing question, I suggest a question reading rather than a full birth chart reading. I cast the chart for the moment your question reaches me and read the question from it, using whatever birth details you have for context.
If you order a full birth chart reading without a time, ask the astrologer what they will and won't be able to read. An honest reading without a time stays with the signs, the aspects and the timing techniques that don't need the rising sign. It should not hand you a rising sign and houses it can't know.
Common questions about birth times
Can I find my rising sign without my birth time? Not reliably. The rising sign depends on the time, to within an hour or two, and on the place of birth. Quizzes that guess it from your personality are guessing. Rectification can narrow it if you know roughly when you were born.
Can an app or calculator find my birth time? No calculator can recover a time from a date alone. A birth time calculator can only be a rectification tool: it tests times against events you enter, with the same uncertainty as any rectification.
What time do astrologers use when the birth time is unknown? Usually 12:00 noon, which keeps every planet within half a day of its true place, or sunrise, which puts the Sun on the rising degree.
Does daylight saving time matter? Yes. Your certificate shows local clock time, which may have been daylight saving or wartime time. An astrologer converts it to Universal Time before casting the chart, so give the time exactly as written.
My parents disagree about the time. Which do I use? A written record made on the day beats memory. If there is none, use the time that comes with a concrete detail, and tell your astrologer about the disagreement.
- Claudius Ptolemy, Tetrabiblos III.2, "Of the Degree of the Horoscopic Point," tr. F. E. Robbins, online at LacusCurtius.
- Vettius Valens, Anthology I.4, "Finding the Ascendant," tr. Mark T. Riley, free PDF at Skyscript, p. 8.
- Rodden Ratings and rectified data: Astro-Databank, Help: RR. Keanu Reeves' data: Astro-Databank.
- Where to order a birth certificate: CDC, Where to Write for Vital Records. The U.S. Standard Certificate of Live Birth, rev. 2003, item 2.
- State examples: Missouri vital records FAQ; Minnesota Department of Health.
- Your right to your medical records: HHS, Your Medical Records.
- War Time and daylight saving: Wikipedia. Horoskopos as "hour marker": Wikipedia, "Ascendant".
- Sign changes, rising-sign durations and the checker: computed for this article with the Astronomy Engine ephemeris, tropical zodiac, births 1925 to 2015.
Roman OleksandrHellenistic astrologer. He reads charts from Valens, Dorotheus, Paulus and Ptolemy in translation, and every statement in a reading traces back to a named technique. How he reads a chart