Astriel
MenuClose

Two charts

Composite chart calculator

Calculate planetary midpoints between two birth charts. Opposite or uncertain positions stay labelled as unavailable.

  1. First person
  2. Second person

Enter the first person

Use birth details that you have permission to enter. Both charts and the comparison will be saved privately. Enter your own email at the final step.

Date of birth

Use the local birth date in the modern (Gregorian) calendar, from 1600 to today.

Time of birth

Local birth time. For 2:30 pm, enter 14:30.

If the end is at or before the start, the range ends the next day. Equal times cover a full day.

We check the whole period. The Ascendant and houses are left out.

We check the whole local day and show any possible sign changes. The Ascendant and houses are left out.

Placidus uses your birth time to calculate unequal houses. Whole Sign gives each sign one house. Both need an exact time.

Choose the matching town or city on the next step.

Filter by country (optional)

Your chart is private. Sharing is always your choice.

A composite creates a new set of positions

A midpoint composite takes the shorter arc between matching planets in two natal charts. The midpoint of the two Suns becomes the composite Sun; the same calculation applies to each supported body.

If one Sun is at 10° Aries and the other at 10° Gemini, the shorter arc is 60°. Its midpoint is 10° Taurus. This is a constructed position, not the Sun at a shared birth moment.

What the composite can describe

Astrologers use a composite as a symbolic chart of a relationship considered together. Synastry keeps the two people separate and compares their contacts. The methods provide different perspectives; one does not confirm the other.

Exactly opposite positions have two equally short arcs, so a unique midpoint is unavailable. Uncertain natal positions also prevent this calculator from presenting an exact midpoint. Composite houses are not supplied.

Use synastry to compare possible contacts when birth times are uncertain.