Free Davison Chart Calculator
Enter two sets of birth details to calculate the Davison relationship chart for the midpoint between the two births.
What is a Davison chart?
A Davison chart, or Davison relationship chart, takes its planetary positions from the moment halfway between two births. It uses a real calculated date and time at a derived geographic midpoint. The Moon has an actual phase, and the planets retain the motion they had in that sky. Astrologers time the chart from that midpoint date.
Ronald C. Davison described the method in Synastry. His book adjusts the calculated time so the relationship Midheaven matches a midpoint of the natal Midheavens. Augurine retains the UTC midpoint instant. It also takes the shorter arc between the birth longitudes, while the book uses their arithmetic mean. The Davison reading guide explains these conventions and their effect on houses.
How the Davison chart differs from the composite chart
The composite chart takes the midpoint of each pair of natal planetary longitudes along the selected arc. Its planetary set can contain positions that never occurred together in a real sky. Composite charts also have houses; their angles and house cusps are derived by the chosen composite method.
The Davison chart instead finds the actual midpoint moment between two births and casts a chart for that time and place. Progressions therefore start from a dated sky, with the Moon’s phase and planetary speeds intact. Practitioners often compare the two chart methods to see which describes the bond more closely. Compare the results with the composite chart calculator or the coalescent chart calculator, and see the full breakdown in our Davison vs. composite chart guide.
How the Davison chart is calculated
Two averages build the chart. For time, the calculator converts both birth moments to the Julian Day scale, takes the midpoint, and converts back to a calendar date and clock time. For place, it averages the latitudes and takes the shorter-arc midpoint of the longitudes. A chart is then cast for that moment and location, with no time adjustment to match the midpoint of the natal Midheavens. When the signed birth longitudes differ by more than 180°, our longitude convention puts the midpoint about 180° from Davison’s arithmetic result, with a substantial change in the local house wheel.
Reliable birth times determine the midpoint clock time and its local horizon. An uncertain birth time can change the Moon’s sign or its aspect exactness as well as the angles and house placements. The calculator withholds houses when a birth time is unknown, so the remaining reading begins with planetary positions whose uncertainty is carried by the inputs.
How to read each placement in your Davison chart
Because the Davison chart is a real natal-style chart, you read it body by body, then by house and aspect. Each card covers what a placement tends to describe about the relationship itself, not either person alone. Start with the Sun, Moon, and Ascendant, then read the rest against them.
Sun
The relationship's purpose and vitality
The Davison Sun points to what the relationship is organized around, its reason for being and where it finds energy. The sign colors that purpose and the house shows the area of life where it plays out. A well-supported Sun tends to give the bond a clear center, so read it first and then check what helps or challenges it.
Moon
Emotional baseline and comfort
The Davison Moon describes the emotional weather of the partnership, how the two of you settle and feel safe together. Its sign gives the instinctive tone and its house shows where the relationship goes for comfort. Hard aspects to the Moon often mark the moods that need tending, while softer ones show where ease comes without much effort.
Ascendant
How the bond meets the world
The Davison Ascendant is the relationship's front door, the impression it gives and the way it tends to start things. Because angles depend on the minute of birth, it only appears when both birth times are exact. When you have it, the rising sign and its ruler add a great deal to how the partnership presents itself and where it instinctively heads.
Midheaven
Shared direction and public role
The Davison Midheaven marks where the relationship is heading and how others see it, the shared goals and standing the bond reaches toward. Like the Ascendant, it needs both exact birth times to appear. Its sign and any planets near it hint at what the partnership tends to build in the world, whether that is a home or a shared undertaking.
Venus
Affection and shared values
Venus in the Davison chart holds the relationship's love language, how affection is shown and what the two of you treasure together. Its sign sets the style, from cozy to formal to adventurous, and its house shows where appreciation and pleasure concentrate. Venus in contact with the Sun, Moon, or Mars often describes how warmth and desire sit together in the bond.
Mars
Drive and friction
Mars shows where the relationship spends its energy and how it handles wanting and conflict. A well-placed Mars gives the bond drive and heat, while a strained one marks where friction tends to flare. The house says which area gets the push and the aspects say whether that push moves with the relationship or against it. Read Mars alongside Venus for the fuller attraction picture.
Mercury
Communication style
The Davison Mercury governs how the two of you talk, plan, and make sense of daily life. Its sign shows the conversational style and its house shows what you tend to talk about most. Easy Mercury aspects make understanding come naturally, while friction here often shows up as crossed wires, usually workable once you name the pattern behind them.
Jupiter
Growth and generosity
Jupiter in the Davison chart marks where the relationship grows and feels generous, the parts of life that open up when you are together. Its house shows where good faith and opportunity tend to flow, and its aspects show how far that expansion reaches into the rest of the chart. Jupiter can also over-promise, so read it for scale as much as for blessing.
Saturn
Commitment and the tests
Saturn shows where the relationship is asked to grow up: the responsibilities it carries and the work that earns durability. Its house names the arena of that work and its aspects show whether Saturn steadies the chart or weighs on it. Contacts between Saturn and the Sun or Moon are a classic marker of long-term staying power, tests included.
Reading the Davison chart with transits and progressions
The midpoint date gives timing techniques an epoch. Secondary progressions move one day forward for each elapsed year; converse directions move one day backward. A transit compares the sky of the date being studied with the midpoint positions. The progressed Moon’s change of sign often marks a shift in the relationship’s emotional rhythm, while Saturn crossing an angle usually brings responsibilities into sharper focus.
For a step-by-step approach to interpretation, see how to read a Davison chart, and for the placements that tend to carry the most weight, the best Davison chart aspects.
Davison chart guides
New to the technique? Start with what a Davison chart is and how to read a Davison chart, then compare the two main relationship charts in Davison vs. composite or see all three approaches side by side in synastry, composite, and Davison.
For interpretation, the Davison chart placements hub covers the Sun, Moon, Venus, and Mars through all twelve houses. To weigh a bond's staying power, read the Davison chart marriage indicators. You can also blend the same two births a different way with the composite and coalescent chart calculators.
Related Free Tools
Compatibility Calculator
Compare two birth charts for synastry aspects and compatibility score.
Composite Chart Calculator
Calculate the composite midpoint chart for any relationship and read it as a shared symbolic pattern.
Coalescent Chart Calculator
Blend two birth charts into Grinnell's coalescent chart, where each body carries its own harmonic and the closest shared placements run hot.
Synastry Aspect Grid Calculator
Free synastry aspect grid calculator. Builds the planet-by-planet inter-aspect matrix between two charts with the exact orb, harmonious or challenging tone, and applying or separating shown where chart speeds resolve it. No compatibility score.
Sun Moon Midpoint Calculator
Find your Sun/Moon midpoint (the lunation point or inner marriage) by degree, sign, and house. Includes synastry context and conservative cosmobiology orbs.
House Overlays Synastry Calculator
Free bidirectional house overlays synastry calculator. See exactly which of your partner's houses each of your planets activates, and which of theirs land in yours, with house emphasis tally and Whole Sign or Placidus support.
Moon Phase Compatibility
Compare two birth dates to see if your moon phases form a full moon. Twin flame, soulmate, complementary, or contrasting verdict.
Descendant Sign Calculator
Find your Descendant sign and discover what you seek in partnerships, relationships, and one-on-one dynamics.
Frequently Asked Questions
What is a Davison chart?
A Davison chart, also called a Davison relationship chart, is calculated from the midpoint in time and space between two births. Unlike a composite chart's abstract planetary midpoints, the Davison chart is cast for a calculated moment and location, so many astrologers use it with transits and progressions.
How is a Davison chart different from a composite chart?
Both are relationship charts, but they are 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 chart for that moment and place. Transits and progressions are more straightforward on the Davison chart, while their use on composites is debated.
Can I run transits to a Davison chart?
Many astrologers do. Because the Davison chart is cast for a calculated time and location, it can be compared with transits, progressions, and returns when reviewing relationship timing. Interpret those contacts alongside the wider chart and the relationship's circumstances.
Do I need exact birth times for a Davison chart?
Reliable birth times are needed for houses, angles and sect. With known birth dates, the midpoint date remains reliable, but uncertain times can change the Moon's sign and occasionally a fast inner planet's sign. The Moon moves about 13° a day, so a 12-hour uncertainty in the midpoint time moves it about 6.5°.
How accurate is the Davison chart calculator?
The midpoint date, time, and geographic coordinates are derived from both birth data sets, then a natal-style chart is cast for that derived moment and location. Exact birth times matter most for the midpoint time, Ascendant, houses, and angular placements.
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.
How do you read a Davison chart?
Read it like any natal chart, only for the relationship instead of a person. Start with the Sun for the bond's purpose, the Moon for its emotional tone, and the Ascendant for how it presents, then work through Venus, Mars, Mercury, and the outer planets by sign, house, and aspect. The results here label every placement so you can take them one at a time.
Can you calculate a progressed Davison chart?
Yes. Because the Davison chart is cast for a real date, time, and place, you can run secondary progressions or current transits against it the same way you would a birth chart. This calculator produces the base Davison chart; progressions are then read forward from that midpoint moment.
Can a Davison chart show marriage potential?
It can highlight themes many astrologers associate with lasting commitment, such as supportive Sun and Saturn contacts or an emphasized 7th house, though no chart guarantees an outcome. Read those placements as tendencies and timing testimony you weigh alongside each person's own chart, not as a verdict.
Where is a Davison chart located?
Its location is the geographic midpoint between the two birthplaces, which can land somewhere neither person has been, sometimes mid-ocean. That is normal. The coordinates only set the chart's houses and angles; nobody needs to travel there for the chart to be valid.
Is the Davison chart better than the composite chart?
Neither is better; they answer slightly different questions. A composite chart maps the relationship's internal patterns from averaged midpoints, while the Davison chart gives the bond a real moment in time and space that carries transits and progressions cleanly. Many astrologers cast both and read them together.
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