What a progressed chart is
A progressed chart is your birth chart advanced in real time at a symbolic speed: one day of planetary motion after birth stands for one year of life. Born 1 January? Your progressed chart for age 30 is the sky as it actually stood 30 days after your birth, re-cast with the same ephemeris that built your natal chart.
Because the planets barely move in that window, the progressed chart looks almost like your natal one — the outer planets sit in the same signs for years, the progressed Sun creeps about one degree per year, and only the Moon travels noticeably (12–14° per year, a full sign every two-and-a-half years). That slow drift is the point: progressions are traditionally read as inner development, the same chart maturing rather than new weather arriving from outside (which is what transits describe).
How we compute it
The engine takes your birth instant, adds exactly one day per year of age, and evaluates planetary geocentric ecliptic longitudes at that moment with sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine) — the same sub-arcsecond VSOP87/ELP models used for the natal chart, with no rounding or mean-motion shortcuts.
Progressed-to-natal aspects are then found by measuring each progressed planet against each natal planet, using classical orbs (6° for conjunctions and oppositions, 4° for trines and squares, 3° for sextiles) and listing the tightest first. The solar arc is the exact difference between your progressed and natal Sun, added to every natal position to produce the directed chart.
What you get
After entering your birth data and an age:
- The full progressed chart at that age — every planet's sign and degree, with how far it has drifted from natal.
- A list of progressed aspects to your natal planets, tightest orb first, with their traditional meanings.
- Your primary solar arc at that age (to 0.01°) and the sign it reaches, the ruler of the arc's directed chart.
- A timeline of progressed Moon sign ingresses — which cycle you are in now and when the next one falls.
How practitioners read progressions
The conventional hierarchy is blunt: watch the progressed Moon. It changes sign roughly every 2.5 years and is treated as the hand of the progressive clock — a Moon progressing into Sagittarius, say, is read as a stretch where the chart's emotional weather turns exploratory. The progressed Sun's slow ingress (about one sign every 30 years) frames whole eras, and outer-planet progressions are usually ignored at the sign level because they barely move.
Aspects are read as they form: a progressed planet conjuncting a natal planet is treated as an inner theme coming to a head, which is why this tool sorts by orb — a 0.5° orb is 'close to exact' in a way a 5° one is not. Because everything moves so slowly, a progressed aspect can stay in orb for a year or more; that endurance is considered the point.
A worked example, with real numbers
Take a chart cast for 1 January 2000, 17:30 UTC in London: natal Sun 10.6° Capricorn, natal Moon 16.1° Scorpio, Ascendant 28.8° Cancer. Progressed thirty days forward — age 30 — the actual ephemeris puts the progressed Sun at 11.1° Aquarius (it has crossed the sign border by half a degree) and the progressed Moon at 18.4° Sagittarius.
Sampling the same calculation at half-year steps shows the progressed Moon entering Sagittarius at about age 28.5 and Capricorn at about age 30.7 — a 2.2-year cycle, matching the technique's expected tempo. The solar arc at age 25 comes out at 25.46°: almost exactly one degree per year, which is the technique's signature and a quick sanity check that the math is real.
What this tool does not claim
There is no scientific evidence that the sky one month after your birth describes your thirtieth year. Controlled studies (we cite Carlson's 1985 double-blind test below) have not supported astrological prediction, and the day-for-a-year symbol itself has no physical mechanism — a conventional, not astronomical, speed-up of time.
Within the tradition, progression is honestly a symbolic device: it asks you to read slow inner drift rather than forecast events. Treat the timeline as vocabulary for reflection. The astronomy we publish is exact; the interpretation is inherited symbolism, clearly labelled as such.
Progressions vs transits vs solar arc
Transits bring the live sky to your chart — actual planets overhead today aspecting your natal degrees, the loudest and fastest signal. Progressions move your own chart, glacially, describing the same territory as it matures. Solar arc splits the difference: every position, angles included, shifted forward by the Sun's progressed distance — one shared dial instead of ten independent movers.
Most astrologers weight transits highest for event timing and progressions highest for inner development; this tool covers the latter two, while current transits live in the Transits & Progressions calculator.
Our method in one line
Progressed positions are real ephemeris evaluations at birth + (age in days) — sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine) — with natal-chart aspects measured by shortest arc and orbs stated above. Reviewed by Dr. Amara Osei, Astronomy Reviewer.
Step by step
- 1
Enter your birth data
Date, time and place — the same inputs as the natal chart, resolved against real time zones including DST.
- 2
Pick an age to examine
The progressed chart recomputes instantly: it is simply the sky at birth plus that many days.
- 3
Read the aspects and the arc
The tightest progressed-to-natal aspects head the list, with the solar arc and its ruler beneath.
- 4
Scan the Moon timeline
The ingress list shows your current progressed-Moon cycle and the next few, roughly 2.5 years apart.
Tip — Compare a progressed Moon sign with the transiting Sun or Jupiter for the same years — practitioners read those overlaps as amplified chapters.
Frequently asked questions
- What do secondary progressions mean?
- It is the oldest large-scale timing technique in Western astrology: one day after birth symbolically equals one year of life. Ptolemy describes the underlying 'return' logic in the 4th century; the day-for-a-year extension became standard in the 20th century. The progressed chart is your natal chart, advanced — not a new chart.
- Why does my progressed chart look almost identical to my natal chart?
- That is exactly what it should do. Thirty years of life equals thirty days of sky: the outer planets have barely moved, your progressed Sun has drifted about 30°, and only the Moon has relocated signs. If a 'progressed' tool shows you dramatic differences, it is probably showing transits instead.
- Do I need my exact birth time for progressions?
- For planet positions in signs, no — dates are enough. The progressed angles (Ascendant/MC) and houses are where birth-time accuracy matters most, so with an unknown time we flag the house-dependent parts as approximate.
- What is the solar arc, and how is it different?
- Solar arc directed symbolism adds one number — the Sun's progressed distance, about 1° per year — to every natal position at once, so a single 'directed' point can square or trine natal planets anywhere in the chart. Where progressions watch each planet's own drift, the arc treats the chart as one moving whole.
- Is my birth data private?
- Calculations run entirely in your browser. Your birth data is never uploaded, never stored on a server, and never shared. The progressed chart is computed locally in your browser and nothing is uploaded.
Written by
Elena Marchetti
Founder & Staff Astrologer
Methodology reviewed by
Dr. Amara Osei
Astronomy Reviewer
Published 2026-10-01 · Updated 2026-10-01 · Calculated with sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine)