Without a time the planets are still worth having and the angles are not computable at all. The tool omits the ascendant, midheaven and houses rather than printing something invented, and this page is about what survives.
A birth chart needs three inputs: a date, a place and a time. Lose the time and the chart splits cleanly into a part that still works and a part that does not, and the split is sharper than most people expect.
What survives is everything driven by the planets' own motion. Their positions change slowly, so a day of uncertainty moves most of them less than a degree. What does not survive is everything driven by the Earth's rotation: the ascendant, the midheaven and every house cusp in every system.
That second group is not merely imprecise. Over twenty-four hours the ascendant travels the entire zodiac, so with no time at all every sign rises at some point and the rising sign is not a wide estimate but no estimate. The distinction matters, because an unreliable number and no number are different things, and only one of them can be quoted with a caveat.
There is no computation that recovers a missing birth time, and it is worth being clear about why rather than just asserting it. The ascendant depends on the local sidereal time, which depends on the clock time. With the clock time unknown across a full day, the sidereal time is unknown across a full rotation, and the ascendant formula returns a different answer for every minute you might substitute.
The planets are different because their positions come from the ephemeris as functions of the date, and the date is known. The tool evaluates them at a specific instant regardless, so when the time is unknown it has to pick one; what it does not do is pretend the angles can be handled the same way.
Two conventions exist for coping and both are worth recognising. A noon chart substitutes twelve o'clock, which puts the planets near the middle of their day's range and minimises the worst-case error; the angles it produces are arbitrary. A solar chart abandons the ascendant and puts the Sun's sign on the first house instead, which produces a house layout that is defined but is not the one a known birth time would have given. Neither recovers information. Both are ways of filling a hole so the drawing looks complete.
A timeless chart is still a real chart, and it is worth knowing what it supports. Sign positions for nine of the ten planets are solid. Aspects between planets are solid, with the Moon's carrying a caveat. Retrograde status is solid. The elemental balance across the planets is solid.
What it does not support is anything involving houses. No planet has a house. There is no rising sign, no midheaven, no chart ruler in the usual sense, and no angular emphasis. Since a large share of modern interpretation is house-based, that removes more than it might sound like: a great deal of what people expect from a chart reading is simply not available.
The reasonable response is to read what is there and stop. A chart with nine reliable sign placements and a full aspect pattern is a substantial object. Treating it as a damaged version of a house chart is less useful than treating it as a complete version of a different thing.
The numbers are the point of this page, so here they are. Taking a full day of uncertainty and measuring from a noon estimate, so twelve hours either way in the worst case, this is roughly how far each body can be from where you think it is.
The Sun moves about half a degree in twelve hours. Mercury at full speed manages a little over a degree, Venus rather less, Mars under half. Jupiter and Saturn move a tenth of a degree or so, and Uranus, Neptune and Pluto are effectively stationary on this timescale. Every one of those is inside the smallest orb this site uses, which means the aspect pattern between the outer planets survives an unknown birth time intact.
The Moon is the exception and it is a large one. It covers between about six and seven and a half degrees in twelve hours depending on where it is in its orbit. That is a quarter of a sign, so if the Moon sits within seven degrees of a sign boundary at noon, its sign is genuinely undetermined. It is also comparable to a whole aspect orb, so lunar aspects can appear or vanish depending on which hour you assume.
Against all of that, the ascendant moves fifteen degrees an hour and three hundred and sixty degrees in a day. There is no useful number to quote for it, which is why the tool prints none.
The live argument here is about rectification: the practice of working backwards from events in a person's life to the birth time that would explain them. Practitioners who do it regard it as a skilled technique with a long history. Practitioners who do not regard it as fitting the answer to the data after the fact.
Both descriptions are accurate, which is the awkward part. Rectification is genuinely old and genuinely skilled, and it is also a procedure in which the practitioner chooses a time that makes the chart agree with a life they have already been told about. Two competent rectifiers working on the same person routinely produce different times, and there is no procedure for deciding between them. This site does not offer rectification and takes no position on whether it works, beyond noting that it is a practice rather than a calculation.
A smaller disagreement concerns whether to draw a timeless chart at all. Some practitioners will not read without a time, on the grounds that a chart missing its angles is missing its structure. Others read sign and aspect material happily and simply decline the house questions. That is closer to what this tool assumes, and the choice is defensible either way.
The reason the loss falls where it does is that a birth chart mixes two different clocks. Planetary positions are set by orbital motion, which is slow: the fastest of them, the Moon, takes a month to go round. The angles and houses are set by the Earth's rotation, which takes a day.
So an uncertainty of one day is a small fraction of every orbital period and a full cycle of the rotational one. That ratio is the whole story. It is not that houses are more delicate or more advanced; it is that they are keyed to the fastest motion in the system, and a day of ignorance is total ignorance about a daily quantity.
A house is a division of the local sky, which requires an exact time and an exact place to draw. Without the time there is no local sky to divide, only a date on which the Earth happened to be somewhere in its orbit. The planets are still where they were, because they do not care what the clock said. Everything else in a chart is downstream of a rotation that nobody wrote down.
Missing birth times are the normal historical condition rather than an unusual problem. For most of the period in which astrology has been practised, ordinary births were not timed. Clocks were rare, then imprecise, and the minute of a birth was not the sort of thing anyone recorded unless the child was royal.
That scarcity shaped the technique. Rectification methods exist in medieval Arabic and Latin sources precisely because practitioners needed a way to proceed without a recorded time, and the elaborate machinery around them is a response to a real and constant difficulty. The prominence of the ascendant in the tradition and the unreliability of birth times sat side by side for most of astrology's history.
Reliable birth times are a recent and uneven development, arriving with hospital birth records and civil registration, and they are still not universal. Where a certificate records a time it is often rounded to the nearest five or fifteen minutes by whoever was holding the clipboard, which is accurate enough for a rising sign and not accurate enough for a rising degree. The modern habit of quoting an ascendant to the arc-minute rests on a chain of documentation that is usually weaker than the number implies.
The most common error is accepting a chart that quietly used noon. Most software substitutes twelve o'clock when no time is given and then prints an ascendant, a midheaven and twelve house cusps exactly as if they had been computed from something. They were computed from an assumption, and the output does not distinguish the two. If you have ever been given a rising sign without being asked for a birth time, that is where it came from.
The second is treating an approximate time as a known one. Morning, or around teatime, or the family story about the church bells, are all considerably better than nothing and all considerably worse than a record. An hour of uncertainty moves the ascendant fifteen degrees and can move it into the next sign; four hours makes the rising sign a coin toss between two or three candidates. The right response is to hold the angles loosely rather than to drop them, and to know which of the two situations you are in.
The third is assuming a rectified time is a discovered one. Rectification produces a time that fits a story, and the fit is the method rather than evidence for the result. If a rectified ascendant is later contradicted by a birth certificate, the certificate wins, and the fact that the rectified chart had seemed to describe the person well is exactly the thing that should have been treated cautiously in the first place.
Cast your own chart and see it in place.