How is Portal height in the nether determined?

This question was spurred by watching someone creating a portal on a hill in the overworld, and spawning above a sea of lava. I thought the two co-ordinates were related somehow.

In short does the Y co-ordinate of your overland portal effect the nether portal Y co-ordinate?

Solution 1:

No, the height is in practically no way correlated between the two dimensions. As the relevant Minecraft wiki article explains, Minecraft will try to find the valid area that's closest to the destination X and Z coordinates. To be valid, the area needs to have a flat solid ground and enough space to accomodate the destination portal.

Only in the rare care of no valid area being available in the general neighborhood of your destination will Minecraft use your current height as the generated portal height, and only if it's in the 70-118 range (= above sea level).

Be aware that this only happens if there's no already active portal in roughly a square overworld kilometer, otherwise Minecraft will simply use the existing portals.

If you find the automated placement unsatisfactory, you can always DIY.

Solution 2:

I just ran a quick test-run and discovered that there is an interesting difference in Y coordinates between Overworld and Nether portals.

As you can see, standing at the entrance to the Nether placed me at y: 6.62~~

Immediately upon entering the Nether, however, I was met with a wildly different coordinate. I was apparently located at y: 71.62~~

Clearly, this can mean only one thing.

The Nether is in Heaven.

Anyway, I tried it again; this time building the Overworld portal somewhat higher:

When I entered the Nether at y: 11.62~~ (5 blocks higher than the previous), I still ended up in the same location on the Nether end. (y: 71.62~~)

From what I can tell, the Overworld y: coordinate has no effect on your y: coordinate within the Nether.