Tropical and sidereal — which the app uses

Every chart the app casts is tropical. There is no zodiac switch, on any plan.

This used to be listed as a Plus feature on our pricing pages. It should not have been — the toggle was never available to subscribers — so we have removed the claim rather than leave people paying for something they could not reach. If you took Plus expecting a sidereal toggle, write to us and we will make it right, refund included.

What the difference actually is

Both zodiacs divide the same circle into the same 64 gates. They disagree about where the circle starts.

• Tropical anchors zero degrees to the March equinox — the Sun's position at the moment spring begins in the northern hemisphere. It is a seasonal frame.
• Sidereal anchors to the fixed stars. It is a stellar frame.

Because the Earth wobbles slowly on its axis, the two frames drift apart by roughly one degree every seventy-two years. Today they differ by about twenty-four degrees — around four gates.

So the same birth moment produces two genuinely different charts. Different gates, often a different profile, sometimes a different type. Neither is a corrupted version of the other; they answer slightly different questions.

Which one mainstream Human Design uses

Tropical. The system as it is taught and published almost everywhere uses the tropical zodiac, and that is what the app calculates. If you have had a reading elsewhere or used another calculator, it was almost certainly tropical too, which is why your charts will agree.

A minority tradition works sidereally and finds it more accurate in practice. That is a real position, honestly held. It is simply not what this app does.

If you want your sidereal placements

Write to us with the name on your chart and we will run them by hand and send them back. The underlying maths exists in our codebase — it is the interface that does not — so this costs us a few minutes and costs you nothing.

Will it come back?

Possibly, and we are not going to attach a date to it. What we will not do again is list it as a feature before it is one. If it ships, this article changes the same day.