Free Davison Chart Calculator
Enter two sets of birth details to calculate the Davison relationship chart — the real birth chart of your relationship.
What is a Davison relationship chart?
A Davison chart (also called a Davison relationship chart) is a chart cast for the exact midpoint in time and space between two births. Unlike the composite chart, which averages planetary positions to create an abstract chart, the Davison chart represents a real moment in time at a real location. This makes it a valid chart for transits, progressions, and solar returns — you can track timing in the relationship just as you would for a person.
The technique was developed by British astrologer Ronald C. Davison in the mid-20th century. The midpoint date is calculated by averaging the Julian Day Numbers of both births, the midpoint location is the geographic average of both birth places, and a full natal chart is cast for that derived moment and place. Our calculator uses NASA's ANISE toolkit for arc-second planetary precision.
How the Davison chart differs from the composite chart
The composite chart is built by averaging the positions of each planet in two natal charts — your Sun's longitude plus their Sun's longitude divided by two, and so on for every planet, angle, and point. The result is a mathematical abstraction: a chart that represents the relationship symbolically but does not correspond to any real moment in time or location in space. Because of this, a composite chart cannot technically receive transits or be progressed — it has no actual birth.
The Davison chart solves this by identifying the actual midpoint moment between two births and casting a genuine natal chart for that time and place. Because it is a real chart, it supports transits, secondary progressions, and solar returns — making it a powerful tool for tracking the timing of events in the relationship itself. Astrologers often use both: the composite for its psychological portrait and the Davison for timing work. Compare the two outputs side by side using our composite chart calculator, and read the full methodological breakdown in our Davison vs. composite chart guide.
Key Davison chart placements to look for
Because the Davison chart is a true natal chart, you read it the same way: start with the Sun for the relationship's core identity, the Moon for its emotional needs, and Venus and Mars for how attraction and desire operate between you. The Ascendant — when both birth times are exact — describes how the relationship presents itself to the world.
Pay special attention to planets in angular houses (1st, 4th, 7th, 10th), which dominate the relationship's expression. Saturn placements show where the relationship demands maturity and commitment. Jupiter shows where it expands easily and feels generous. The aspects table reveals whether the chart's energies flow smoothly (trines, sextiles) or create productive tension (squares, oppositions) that drives growth.
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Frequently Asked Questions
What is a Davison chart?
A Davison chart (also called a Davison relationship chart) is a relationship chart calculated from the midpoint in time and space between two births. Unlike the composite chart's abstract midpoints, the Davison chart corresponds to a real moment in time at a real location, making it a valid chart for transits and progressions.
How is a Davison chart different from a composite chart?
Both are relationship charts, but they're constructed differently. A composite chart averages each planet pair's positions. A Davison chart finds the midpoint date, time, and location between two births, then casts a real chart for that moment and place. The Davison chart can be progressed and transited; the composite cannot.
Can I run transits to a Davison chart?
Yes — this is one of the Davison chart's key advantages. Because it corresponds to a real moment in time, you can track transits, progressions, and solar returns to the Davison chart just as you would for a natal chart. This makes it especially useful for timing relationship milestones.
Do I need exact birth times for a Davison chart?
Exact birth times produce the most accurate Davison chart, particularly for the midpoint time calculation and house placements. Without birth times, the midpoint date and planet sign positions are still reliable. You can indicate your confidence level for each person's birth time.
How accurate is the Davison chart calculator?
Our calculator uses NASA's ANISE toolkit for all astronomical computations, providing arc-second precision. The midpoint date, time, and geographic coordinates are calculated precisely from both birth data sets, then a full natal chart is cast for that derived moment and location.
Who developed the Davison chart technique?
The Davison relationship chart was developed by British astrologer Ronald C. Davison in the mid-20th century. His approach of finding the temporal and spatial midpoint between two births offered an alternative to the composite chart that produced a chart anchored in real time and space.