What exactly are the boundaries between Android density buckets?

Question

I want to classify our inventory of Android development devices based on screen density.

I easily discovered the physical densities for each device in PPI units. This is standard information given as part of the product specification.

However, given the PPI number, how can I confidently classify each device into a density bucket? The Android documentation gives a prime number for a density bucket, as well as a chart showing approximate and overlapping ranges.

For example, consider a device with a screen density of 370 PPI. The Android XHDPI bucket is "~ 320" and the XXHDPI bucket is "~ 420". So which bucket 370 gets in?

I was unable to find an exact specification of where the boundaries between the buckets are; or, if they overlap, exactly how large the overlap is. Is this subjective? Do I really need to run test software on each physical device to determine the bucket?

Answer 1

It seems that the specific density bucket onto which the device falls is determined by the manufacturer and does not comply with a strict formula.

I believe that this definition takes into account the effective density of the screen, as well as the #pixels and physical dimensions of the device, so the selected “bucket” gives the best results both from the size of the asset and from the layout perspective.