The Astrolium Human Design compatibility calculator runs two bodygraphs against each other and returns the dominant connection type — electromagnetic, dominance, compromise, or companionship — plus the gate-level mechanics underneath. Composite channels, electromagnetic completions, compromise gates, dominance per center, and a 0-100 score. Computed from precise birth data on the Swiss Ephemeris, nothing stored.
Most Human Design compatibility tools return a label and a paragraph. Astrolium returns the full mechanical breakdown so you can see which gates create the chemistry, which centers carry the friction, and where the relationship asks for conscious work. For the single-chart bodygraph that feeds both inputs, see the Human Design calculator. For the related astrological compatibility lens, see the synastry calculator.
What the calculator returns
Human Design treats compatibility differently from synastry. Where astrological synastry overlays planetary aspects between two charts, Human Design overlays the gate activations and asks what new mechanical patterns form when both bodygraphs occupy the same space.
The connection type is the dominant pattern across the combined chart. Four possibilities. Electromagnetic relationships build around opposite-gate chemistry — each partner carries gates the other is missing. Companionship relationships build around shared defined gates — easy resonance, sometimes lacking edge. Dominance relationships have one partner consistently broadcasting into the other's open centers. Compromise relationships share hanging gates that never quite complete.
Composite channels are the standout finding most calculators miss. When Person A has gate 1 defined and Person B has gate 8 defined, the relationship has the 1-8 channel of Creative Role Model — a channel neither of them carries alone. This is the relationship's emergent expression: what becomes possible only because the two of you are in proximity. The list of composite channels is often more useful than the score because it tells you what the relationship does in the world.
Electromagnetic gates are the gate-level chemistry layer. The calculator returns each pair and which partner contributes the completing gate. The 3-60 pair where Person A's hanging gate 3 is completed by Person B's gate 60 reads as a specific kind of mutation chemistry — and the same direction tells you who feels completed by whom.
Compromise gates are where both partners carry the same hanging gate. Looks similar to electromagnetic on paper but creates friction without spark. Two people both want to express gate 3 but neither completes it.
Dominance analysis runs center by center. The calculator returns who leads in each of the nine centers and the pattern type. Defined-over-undefined means one partner consistently broadcasts; one-way reception means one partner's gates condition the other. When both partners are aware of these patterns, dominance becomes a gift. When unconscious, it creates the one-sided dynamic that exhausts the open partner.
The connection types in brief
Electromagnetic — Strong chemistry. Each partner completes gates the other is missing. The feeling is being made whole when together, magnetic attraction, and often a rapid sense of recognition. Healthy electromagnetic relationships allow each partner to keep their own design while accessing the completion the other provides. The pitfall is dependency: it can be hard to function alone when you've been completed for so long.
Companionship — Strong friendship resonance. Both partners share many defined centers and channels, so being together feels comfortable and familiar. The terrain is easy because both designs respond to the same energetic information. The pitfall is lack of friction — companionship relationships sometimes lack the contrast that drives growth.
Dominance — One partner consistently leads in shared centers. Works beautifully when conscious — when the dominant partner knows their role and the open partner appreciates the leadership. Becomes problematic when unconscious — the open partner amplifies the dominant partner's energy without realising it isn't theirs, leading to exhaustion or identity confusion.
Compromise — Both partners share hanging gates that don't complete each other. Sameness without spark. Compromise relationships often work as friendships or work partnerships but lack the energetic chemistry that drives romantic intensity. Conscious compromise relationships acknowledge the sameness and find their spark elsewhere.
After the calculator
Once you have the connection type and the dominance map, the next layer is timing. Both partners' transits affect the relationship's electromagnetic completions — when a transit lights up a partner's hanging gate, it temporarily completes a channel that the relationship doesn't usually have. For the daily transit scan on each partner, see the Human Design transits calculator. For the astrological compatibility layer that most Human Design practitioners read alongside, see the synastry calculator and the composite chart calculator.
For the single-chart Human Design entry point, see the Human Design calculator. For the broader natal context, see the natal chart feature.
Cross-link
Pair with the Human Design calculator for the single-chart read, the Human Design transits calculator for daily timing on each partner, the synastry calculator for astrological inter-aspects, and the composite chart calculator for the midpoint chart.