Does Your Birth Chart Repeat? When the Same Planet-Sign Lineup Comes Back

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This page asks a narrower question than its title might suggest. It measures whether the signs of a set of planets come back in the same combination years later. It does not measure whether a whole chart repeats: a repeated set of signs does not mean repeated degrees, aspects, Ascendant or houses, and full-chart recurrence was not measured at all.

The answer depends on how many planets you include. Inside the 140 measured years:

• Sun, Mercury, Venus and Mars: a later return within 60 years happened for 84.1% of the starting time, usually within about 21 years (median).
• Add the Moon: 56.4% within 60 years, with the typical first return about 32 years later.
• Add Jupiter and Saturn: almost never. Only 0.14% of starting time (0.10% with the Moon as well) saw a return within 60 years, and all of those came just under the 60-year limit.
• All nine planets except the Moon, or all ten: none observed within 60 years in this measured window.

These are shares of modelled time in the sky, not shares of people or births. "Within 60 years" is a limit set by the measurement, not a claim about what can happen beyond it.

Calculator note: the free birth chart shows the sign of each planet for one moment. It does not search other years for the same combination. Ask the Astrologist does not compute these figures either.

Six lineups, from four planets to ten

Each level adds planets to the one before it. The Moon is added on its own at three points, so its effect can be seen separately from the slow planets.

Chiron, the Nodes and the angles are not part of any level.

What counts as "coming back"

Start at a moment in the window and note the signs of the planets in a level. That combination comes back if a later stretch with exactly the same signs begins at least one year after the starting moment and no later than the horizon. The one-year minimum stops the same stretch, or a quick return during a retrograde period, from counting as a later year. A stretch has to last for some positive time; a planet that only touches a sign line does not count.

Three horizons were fixed in advance: 15, 30 and 60 years, with a year taken as 365.2425 days. Each horizon looks forward only, and only starting moments whose whole forward horizon fits inside the window were used: up to the end of 2044 for 15 years, the end of 2029 for 30 years and the end of 1999 for 60 years. Starting moments are weighted by time, so a combination that lasts a week counts seven times as much as one that lasts a day.

How often each lineup comes back

Adding the Moon lowers the share for the four fast planets, by about half at 15 and 30 years and by about a third at 60 years, but it is not what stops the larger lineups. The step that matters is adding Jupiter and Saturn, and the nine-planet row, which leaves the Moon out, shows that the slow planets alone are enough to prevent any return within 60 years.

How long until the first return

For the 60-year horizon, the waiting time to the first qualifying return was measured for every starting moment that had one.

The level 6 and 7 returns all fall within three weeks of the 60-year limit. That shows the limit happens to sit just past a near-repeat; it is not a natural cut-off. A longer horizon might find more, and one shorter than 59.95 years would find none. For levels 9 and 10 there is nothing to report.

Why the slow planets block a repeat

This section is background, not a measurement. Mercury and Venus never move far from the Sun, so the Sun-to-Mars lineup comes back fairly often once Mars is in the same sign at the same time of year. Jupiter takes about 12 years to go round the zodiac and Saturn about 29 and a half, so the pair return to nearly the same signs only after about 60 years. Uranus, Neptune and Pluto take roughly 84, 165 and 248 years, so a full set of slow-planet signs belongs to one stretch of years and moves on. How long each planet stays in a sign is set out in how long each planet stays in a sign, why the slow planets mark birth years in slow-planet sign changes and your birth year, and the generational reading in outer-planet signs and generations. None of these approximate periods was used to infer a result; the tables above come from the measured sign changes.

Ruben, looking forward from 1993

Ruben is the fictional chart from how to find aspect patterns: London, 5 January 1993, 12:00 GMT, recomputed with code version 476c723. His signs are Sun Capricorn, Moon Gemini, Mercury Capricorn, Venus Pisces, Mars Cancer, Jupiter Libra, Saturn Aquarius, Uranus Capricorn, Neptune Capricorn and Pluto Scorpio. Only later dates were searched, up to 60 years after his birth (January 2053).

So someone born between 8 and 19 January 2025 shares his Sun, Mercury, Venus and Mars signs, and from 10 to 12 January also his Moon sign, while Jupiter, Saturn and the outer planets are in different signs. That is all the match covers.

How it was measured

This uses the same offline run of the free chart's routines, code version 476c723, as can two people have the same birth chart. Every sign change of the ten planets between 1 January 1920 and 1 January 2060, in both directions including retrograde crossings, was located from the full-precision longitudes, and every resulting stretch was checked against a fresh calculation. For each level, the stretches with an unchanged combination were then compared with every later stretch of the same combination. Shares and waiting times are exact over elapsed time, not counts of sample dates. Dates after publication are computed positions, not forecasts. Small model differences, of the order of minutes for most sign changes, do not change these year-scale results.

A second check: noon dates

As a coarser check, the chart routine was run for London at 12:00 on all 51,135 dates, and a date was counted when the same level combination appeared at noon on some date between one year and 60 years later. The noon shares were 83.4%, 53.1%, 0.13%, 0.10%, 0% and 0% for the six levels, close to the exact results. They are only a cross-check.

Reading it sensibly

A lineup that comes back is not a sign of a shared destiny, and one that does not come back is not a mark of being special. Someone born 32 years after you may share your inner-planet signs; that says nothing about personality, relationships or events, and nothing about how many people share any combination.

Doing the check yourself

1. Read the ten planet signs for your birth from the free birth chart.
2. Choose a level from the first table and keep only those planets.
3. Look up a later date in the same chart and compare the same planets. A match covers signs only, not degrees, aspects, the Ascendant or houses.

Related articles

• Can Two People Have the Same Birth Chart?
• How Long Does Each Planet Stay in a Sign?
• Slow-Planet Sign Changes and Your Birth Year
• Outer-Planet Signs and Generations
• What Is a Birth Chart? A Simple Explanation
• Birth Charts