Progressed chart calculator
Progressed Chart Calculator: A Day for a Year
Secondary progressions read the days after your birth as the years of your life: the sky thirty days later stands for your thirtieth year. Enter your birth data and a date, and this casts that chart and sets it beside the one you were born with.
Your birth data
Your birth details are used only to calculate this chart. They are not saved.
The day of your life
Progressions are usually read for now, but they are just as useful pointed at a year you already know the shape of. Try the year of a move, a marriage or a change of work, and see what the progressed Moon was doing.
The chart is cast for your birth instant plus one day per year of life, with the year measured as a tropical year of 365.2422 days.
Still needed: Birth Date · Birth Time · Birth City
The convention, stated before anything is built on it
Secondary progressions take the ephemeris for the days that followed your birth and let each of those days stand for one year of your life. At thirty-five you are read from the sky of the thirty-fifth day. There is no physical mechanism here and none is claimed; it is a symbolic correspondence astrologers have used since antiquity. One year is taken as a tropical year, 365.2422 days, the Sun's own return period. Some software uses 365.25 instead, or counts whole birthdays. Across a lifetime those variants differ by well under a day of ephemeris, which is a few hundredths of a degree of progressed Moon: real, and far smaller than the difference between two astrologers reading the same chart.
The progressed Moon, and why it gets the attention
The progressed Moon moves about a degree a month and crosses a whole sign in roughly two and a half years, which makes it the only fast hand on this clock. The progressed Sun advances about a degree a year and changes sign once every thirty; the outer planets barely move at all, and in many charts they never leave the degree they were born in. So when people talk about their progressions, they are usually talking about the Moon: which sign it has reached, which house it is passing through, and when it last changed either. That is the placement this page puts first.
Where the schools disagree: the angles
The planets in a progressed chart are not controversial; they are simply the ephemeris. The Ascendant and Midheaven are another matter, because there is more than one rule for moving them. This tool casts the actual chart for the progressed instant at your birthplace, so the angles advance at the rate the Earth really turned, close to a degree a year. Other schools move the Midheaven by Naibod's rate, or by solar arc, and put the angles a fraction of a degree away per year of life. Over a decade that difference can move a progressed Ascendant across a sign boundary, which is exactly the kind of thing worth knowing before you read anything into one.
Progressions and transits are two different clocks
Transits are the real sky, moving at its own speed, the same for everyone alive today. Progressions are a symbolic clock, unique to your birth moment, moving about a degree a year. Most astrologers read them together and treat agreement between the two as the interesting signal, which is a polite way of saying that either one alone says less than it appears to.
What this does not do
It does not date events, and it cannot. A progressed aspect is exact for a stretch of months and describes a theme at most; the same progressed Moon in the same house runs over millions of lives at once. Read it as a slow-moving mood the tradition assigns to a period, and keep your own account of what actually happened separate from it.
Questions about progressions
Why a day for a year?
The correspondence is old, and the usual justification is scriptural rather than astronomical. What can be said in its favour is only that astrologers have worked with it for a very long time and report it as useful. There is no measurement behind it, and this page will not pretend otherwise.
Is the progressed chart more important than the birth chart?
No. Every tradition that uses progressions treats the birth chart as the subject and the progressed chart as a commentary on it. A progressed Sun in a new sign does not replace the one you were born with.
Which date should I enter?
Today, if you want the current picture. A past year, if you want to see what the technique says about a period you already know from the inside. That second use tells you more about how much weight to give it than any amount of reading about it will.
What is a progressed new moon?
The moment the progressed Moon catches up with the progressed Sun, once every twenty-nine or thirty years. Astrologers read it as the start of a cycle. It is visible in this data as a conjunction of the two progressed bodies, and you can find it by stepping the date forward until their degrees meet.
Do progressions need an exact birth time?
For the planets, no more than a birth chart does. For the progressed Ascendant and Midheaven, yes, and rather badly: the angles move about a degree per year of life, so a birth time that is an hour out puts them fifteen degrees out at every age.
The conventions this chart uses
None of these are facts of the sky. Each is a choice astrologers disagree on, so we list ours — a difference from another site can then be traced to its rule instead of blamed on the stars.
- Tropical zodiac
- Signs are tropical, anchored to the March equinox, not to the constellations. Sidereal (Vedic) astrology counts from the stars instead, which currently shifts every position by about 24 degrees — the most common reason two sites disagree about a sign.
- Placidus houses
- Houses are Placidus, the most widely used modern system. Whole-sign or Koch redraw the boundaries: they move planets between houses, never between signs. Beyond the polar circles Placidus is undefined, and we then show the chart without houses rather than guess.
- Mean lunar nodes
- The lunar nodes are mean (averaged). The "true" node oscillates around the mean by up to about two degrees — measured, at most 1°59' across two centuries.
- Mean Lilith
- Black Moon Lilith is the mean lunar apogee. The "true" (osculating) variant can sit up to about thirty degrees away — often a different sign, and the single biggest source of Lilith disagreements.
- Aspect orbs
- Natal orbs: conjunction and opposition 8°, square and trine 7°, sextile 5°, quincunx 3°. Toward the Ascendant and Midheaven the orbs tighten, and the quincunx is not counted there at all. A site with wider orbs lists more aspects, not different planets.
- Sect
- The Part of Fortune follows sect: a day birth (Sun above the horizon) uses Ascendant + Moon − Sun, a night birth the reverse. For night births, calculators that apply the day formula to everyone place it in a different sign roughly nine times out of ten.