How is a grand cross different from a T-square?

A T-square is three planets: one opposition with a third planet square to both ends. A grand cross adds a fourth planet opposite that third one, so there are two oppositions and four squares. Every grand cross contains four T-squares, but this page lists the cross once rather than four times.

Are four planets in cardinal, fixed or mutable signs a grand cross?

Not necessarily. Signs of the same modality are 90° or 180° apart as signs, but the planets’ degrees decide. One planet early in a sign and another late in the next matching sign can be far from 90°. A cross can also mix modalities when a planet sits near the edge of a sign, so this page doesn’t assign a cardinal, fixed or mutable label.

Why does another site show a different result?

Calculators use different orbs, and some include extra points such as the nodes, Chiron or the Ascendant. A square near the edge of its allowance can count on one site and not on another. This page uses Lunara’s settings, listed above, and only the ten bodies.

What does it mean if I don’t have one?

Only that no four of your ten bodies meet all six conditions within these orbs. It doesn’t mean anything is missing from your chart, and the prompt on this page works without a grand cross.

Why does it need a recorded birth time?

The Moon moves about 12° to 15° a day, so whether it makes a square or opposition can change between morning and evening. Slower planets usually keep the same aspects all day, but this page doesn’t guess: it won’t fill in midnight or noon. The full chart’s houses also depend on the exact time.

Free tool · tropical zodiac · ten bodies · checks degrees, not sign labels

Grand cross calculator

A grand cross is four planets that need six connections at once: two oppositions (about 180°) and four squares (about 90°) linking every planet to the two it doesn’t oppose. One opposition with a planet square to both ends is a T-square, not a grand cross. Four planets in signs of the same modality aren’t enough either: the degrees decide. This calculator shows all six connections with their actual degrees. It needs a recorded birth time.

Check six connections, not the shape of a drawing:

Two oppositions between four different planets: A opposite C, B opposite D.
Four squares: A–B, B–C, C–D and D–A.
All six counted at once, each within its allowed orb.

A grand cross isn’t a curse, a health or fate verdict, or a sign of special powers. It’s a geometric pattern between four planets, and the calculator reports only the degrees.

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.

It has no grand cross. Between its ten bodies it has 2 oppositions and one square. A grand cross needs two oppositions between four different planets plus four squares, and these rows don’t make that shape:

Sun–Jupiter opposition, 5.67° from exact (allowed 7.50°)
Jupiter–Uranus opposition, 0.64° from exact (allowed 5.50°)
Moon–Mars square, 6.73° from exact (allowed 7.30°)

A zero here says nothing about the person the chart belongs to; it only means the six connections aren’t all present.

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 counts as a grand cross here

Four different planets where the calculation finds all six aspects: two oppositions with no planet in common, and a square between each planet and the two it doesn’t oppose. The calculator checks degrees, not signs or modality. Planets in signs that look right can miss by a few degrees, and a planet near the edge of a sign can still count.

Conceptual geometry — not a birth chart. Solid lines: the two oppositions (180°). Dashed lines: the four squares (90°). No planets, signs or dates are shown; real patterns are rarely exact and count when each connection is within its allowed orb.

Lunara’s chart allows 6° either side of 180° for an opposition and 5.8° either side of 90° for a square. When the Sun or Moon is one of the pair, the allowance grows by 1.5° (once, even for the Sun and Moon together). When Uranus, Neptune or Pluto is one of the pair, it shrinks by 0.5° (also once). A pair with a luminary and one of those outer planets gets both adjustments. The table shows the allowance used for each pair, and a pair close to its allowance is the part most likely to differ on another site.

These are this site’s settings, not a universal rule. Another calculator may use stricter or wider orbs, or add the nodes, Chiron or the angles, so its answer can differ from this one. If you have three of the four planets, the T-square calculator shows that shape.

A prompt, with or without one

Astrologers often describe a grand cross as four demands pulling in different directions, held in balance only when each gets some attention. You can use that as a reflection whether or not your chart has one. An invented example: “Work, family, rest and a side project all want my Saturday; I’ll give each one a fixed slot instead of letting the loudest win.”

The four things competing for my time this week: ___

One small, fixed slot I’ll give the one that usually loses: ___

Write it wherever you like; this page doesn’t ask for or keep your answers. It’s a reflection, not a reading of your chart or a promise of any result.

Frequently asked questions

How is a grand cross different from a T-square?: A T-square is three planets: one opposition with a third planet square to both ends. A grand cross adds a fourth planet opposite that third one, so there are two oppositions and four squares. Every grand cross contains four T-squares, but this page lists the cross once rather than four times.
Are four planets in cardinal, fixed or mutable signs a grand cross?: Not necessarily. Signs of the same modality are 90° or 180° apart as signs, but the planets’ degrees decide. One planet early in a sign and another late in the next matching sign can be far from 90°. A cross can also mix modalities when a planet sits near the edge of a sign, so this page doesn’t assign a cardinal, fixed or mutable label.
Why does another site show a different result?: Calculators use different orbs, and some include extra points such as the nodes, Chiron or the Ascendant. A square near the edge of its allowance can count on one site and not on another. This page uses Lunara’s settings, listed above, and only the ten bodies.
What does it mean if I don’t have one?: Only that no four of your ten bodies meet all six conditions within these orbs. It doesn’t mean anything is missing from your chart, and the prompt on this page works without a grand cross.
Why does it need a recorded birth time?: The Moon moves about 12° to 15° a day, so whether it makes a square or opposition can change between morning and evening. Slower planets usually keep the same aspects all day, but this page doesn’t guess: it won’t fill in midnight or noon. The full chart’s houses also depend on the exact time. 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. Grand crosses are found by joining the same opposition and square rows the free birth chart’s aspect calculation produces, limited to Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto; nodes, Chiron and the chart angles are left out. Each set of four planets is listed once, with both oppositions first and then the four squares. Text written with AI assistance. A grand cross is a symbolic pattern in astrology, not a prediction, diagnosis or measure of how your life will go.