Free tool · tropical zodiac · ten bodies · geometry only
Birth chart shape calculator
Why are all my planets on one side? This calculator answers the geometric part of that question. It places your Sun, Moon and eight planets around the zodiac, measures every gap between neighbours, and shows the smallest arc that holds all ten and the widest stretch with none of them. It doesn’t give your chart a shape name or a personality label. It needs a recorded birth time.
Example: a fictional chart
This is Lunara’s invented sample chart, not your chart or a real person’s: 1 January 1990, 12:00, London, the same fictional chart as the sample reading. Measured by the same rule as the form below.
All ten planets fit within 228.1° of the zodiac, from Pluto (17° Scorpio) round to Jupiter (5° Cancer) in zodiac order. The widest stretch with none of them is 131.9°, from Jupiter to Pluto.
Zodiac circle, 0° Aries at the left, signs running anticlockwise. Not a house wheel or a picture of the sky. Thick line: occupied arc. Dashed: largest empty arc.
| 1 | Jupiter | 5.1° Cancer |
|---|---|---|
| 2 | Pluto | 17.1° Scorpio |
| 3 | Mars | 10.0° Sagittarius |
| 4 | Uranus | 5.8° Capricorn |
| 5 | Sun | 10.8° Capricorn |
| 6 | Neptune | 12.0° Capricorn |
| 7 | Saturn | 15.7° Capricorn |
| 8 | Mercury | 25.7° Capricorn |
| 9 | Venus | 6.2° Aquarius |
| 10 | Moon | 3.3° Pisces |
| Jupiter → Pluto | 131.9° · largest |
|---|---|
| Pluto → Mars | 22.9° |
| Mars → Uranus | 25.8° |
| Uranus → Sun | 5.0° |
| Sun → Neptune | 1.2° |
| Neptune → Saturn | 3.6° |
| Saturn → Mercury | 10.0° |
| Mercury → Venus | 10.5° |
| Venus → Moon | 27.0° |
| Moon → Jupiter (past 0° Aries) | 121.9° |
Check your chart
Your birth details and chart are kept only in this page’s memory for this calculation, never in the page address or browser storage. If you open your full chart and buy a reading, the details needed to write it are stored with your order.
What this measures
Each planet sits at a position on the zodiac, from 0° Aries round to the end of Pisces. Put the ten in zodiac order and measure the distance from each one to the next, including the jump from the last back past 0° Aries to the first. The biggest of those gaps is the widest stretch of the zodiac with none of your planets in it. Everything else, 360° minus that gap, is the smallest arc that holds all ten.
An empty arc is not an empty house, and it isn’t a missing part of you. It’s a stretch of zodiac longitude where none of these ten planets happened to be. If you want to know which houses are empty, that depends on your birth time and place and is a separate question for the empty house calculator.
Why there’s no shape name here
Astrologers often describe the spread of a chart with names such as bowl, bucket, bundle, locomotive or splash. Those come from Marc Edmund Jones’s classification, and different astrologers apply its boundaries and exceptions differently. This page gives you the measurements those names start from, the occupied arc, the largest gap and every gap in between, and leaves the naming out rather than inventing a threshold. It also doesn’t pick a leading planet or say what the spread means about you.
A reflection
Look at the planet at each end of your occupied arc. Astrologers sometimes treat the two edges of a spread as the places where a chart meets what lies outside it. As a prompt rather than a reading: name one thing in your week that sits right at the edge of your usual routine, and one small step that would bring it inside.
Write it wherever you like; this page doesn’t ask for or keep your answer.
Read more: birth chart aspects calculator · modality calculator · how to read a birth chart.
Frequently asked questions
- Does this tell me if my chart is a bowl, bucket or locomotive?
- No. Those names come from a classification by the astrologer Marc Edmund Jones, and astrologers apply it with different rules and judgement. This page reports the measurements those discussions start from, the occupied arc and the largest gap, without choosing a name for you.
- Is an empty part of the zodiac an empty house?
- No. The empty arc here is a stretch of zodiac longitude with none of the ten planets in it. Houses are a separate division based on your birth time and place. To check houses, use the empty house calculator.
- Is a narrow spread rare or meaningful?
- This page doesn’t give a rarity figure or a meaning. Slow planets such as Uranus, Neptune and Pluto sit close together for everyone born in the same few years, which already narrows part of the spread.
- Why does it need a recorded birth time?
- The Moon moves about 12° to 15° a day, so it can move the edge of the occupied arc between morning and evening. Rather than guess, the page waits for a recorded time. The full chart’s houses also depend on it. Without a recorded time, see the guide to a birth chart without a birth time.
Method: Lunara’s central Swiss Ephemeris calculation, tropical zodiac, geocentric. The Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto are sorted by ecliptic longitude using unrounded positions; nodes, Chiron, the Ascendant, the Midheaven and houses are not used, and nothing is weighted. Gaps are measured in zodiac order, including the one that passes 0° Aries. If two or more gaps are exactly equal, the first in zodiac order from 0° Aries is shown and the tie is stated. Figures are rounded only for display. Text written with AI assistance. A chart’s spread is a symbolic feature in astrology, not a measure of personality or a forecast.