Android PPI Buckets Explained: LDPI to XXXHDPI, in Plain Numbers
If you've ever seen an image folder named drawable-xxhdpi or read a spec sheet that just says "HDPI" instead of a PPI number, this guide translates Android's density-bucket system into plain pixel-density terms — and looks at why a single PPI figure sometimes undersells how much detail a screen can actually pack in.
Quick answerAndroid groups screens into density buckets — LDPI, MDPI, HDPI, XHDPI, XXHDPI, XXXHDPI — so the OS and app developers don't have to reason about every possible exact PPI value. A screen's real PPI gets rounded into the nearest bucket, and that bucket determines both how the system scales UI layouts and which image asset resolution gets loaded.
The core idea is dp (density-independent pixels): a button defined as "48dp tall" should look the same physical size on a low-density screen and a high-density one, even though it occupies a very different number of raw pixels on each. Android converts dp to actual pixels using a scale factor tied to the device's density bucket — roughly, MDPI is the 1x baseline (~160 PPI), and each step up roughly doubles or steps the scale factor, so an XXHDPI screen (~480 PPI, a 3x scale factor) needs an image asset three times the pixel dimensions of the MDPI baseline version to look equally crisp.
This matters beyond Android development, too — the same rounding logic is a useful mental model any time you see a screen described only by a density label instead of a PPI number, whether in a spec sheet, a design tool, or an old device review.
The bucket-to-PPI reference table
These are the standard approximate PPI ranges associated with each bucket. Real devices don't land on the center number exactly — the bucket is the nearest match, not a precise measurement.
Bucket
Approx. PPI
Scale factor
Typical era / device type
LDPI (low)
~120
0.75x
Very old / low-end small screens
MDPI (medium, baseline)
~160
1x
Older basic phones, some tablets
HDPI (high)
~240
1.5x
Older mid-range phones
XHDPI (extra-high)
~320
2x
Mid-range phones, small tablets
XXHDPI (extra-extra-high)
~480
3x
Many current mid-range to upper phones
XXXHDPI (extra-extra-extra-high)
~640
4x
Current flagship phones
To see where a specific screen actually falls, calculate its PPI first — from resolution and diagonal size — and then compare that number against the ranges above. For example (illustrative), a phone at 1290×2796 resolution and 6.7-inch diagonal works out to roughly 460 PPI, which rounds into the XXHDPI bucket even though it's closer to the XXXHDPI boundary than to the XXHDPI center point.
PPI vs. PPI² — density along a line vs. across an area
Quick answerPPI measures pixel density along one dimension (a single inch of line). PPI² (pixels per square inch) approximates density across an area by squaring the PPI value, and because it's a square relationship, small PPI differences turn into much larger PPI² differences — which better reflects how much actual image or text detail fits into a patch of screen.
Here's the part that's easy to miss when comparing two phones by PPI alone: PPI is a linear measurement, but a screen is a two-dimensional surface. Two devices that look only "somewhat" different in PPI can differ substantially in how many total pixels occupy the same physical square inch, because that comparison scales with the square of the PPI difference, not the difference itself.
Example (illustrative): Phone A at 400 PPI has roughly 160,000 pixels per square inch (400²). Phone B at 460 PPI — only 15% higher in PPI — has roughly 211,600 pixels per square inch (460²), which is about 32% more pixels packed into the same square inch. The PPI numbers looked close; the area-density gap is considerably wider.
This is mostly a "sanity check" concept rather than something that changes a buying decision on its own — a modestly higher PPI number can represent a meaningfully denser screen than it first appears, and PPI² is one way to put a number on that. A future version of a PPI/DPI tool could surface this as an extra line in the Screen PPI result breakdown, alongside the standard PPI figure, for anyone comparing pixel density across an area rather than just along the diagonal.
Using this when checking a screen or planning assets
Put together, density buckets and PPI² serve two different practical questions. Buckets answer "which discrete category does this screen belong to, and what does that imply for asset scaling or UI layout expectations?" PPI² answers "how much finer is this screen's detail really, compared to another one, once you account for it being a two-dimensional surface?"
A simple workflow: calculate the exact PPI for a device (from its published resolution and diagonal), match that number against the bucket table above to see which density category it falls into, and if you're comparing two close-looking devices, square both PPI values to see how much the area-density gap actually widens. None of this requires special software — just the PPI figure the calculator already produces, applied to a couple of extra questions.
Calculate exact screen PPI from resolution and diagonal, check print DPI, find required pixel resolution, or compare two screens side by side — instantly, with a device library built in.
What are Android's DPI buckets (LDPI, MDPI, HDPI, XHDPI, XXHDPI, XXXHDPI)?
They're density categories Android groups screens into for choosing image assets and scaling layouts: LDPI (~120 PPI), MDPI (~160 PPI, the baseline), HDPI (~240 PPI), XHDPI (~320 PPI), XXHDPI (~480 PPI), and XXXHDPI (~640 PPI). A screen's measured PPI is rounded to the nearest bucket, and the OS scales dp (density-independent pixel) units accordingly so a button drawn at the same dp size looks the same physical size across devices.
Which DPI bucket does a typical modern phone fall into?
Most current flagship and mid-range phones land in the XXHDPI (~480 PPI) or XXXHDPI (~640 PPI) buckets, since their actual PPI is often in the 400-500 range. LDPI and MDPI are effectively obsolete for phones today and mostly relevant to very old or unusual small-screen devices.
What is PPI² (pixels per square inch) and how is it different from PPI?
PPI measures pixel density along a single line (per inch), while PPI² (pixels per square inch) approximates it as PPI squared, describing pixel density across an area rather than a line. Because PPI² scales with the square of PPI, a modest-looking PPI difference — say 400 vs 460 — turns into a much larger gap in total pixels per square inch, which is closer to how much fine detail (like a photo or a dense UI) a given patch of screen can actually display.
Why would a developer or designer care about pixel-density buckets instead of raw PPI?
Raw PPI is a continuous number, but Android (and most asset pipelines) work in discrete density buckets, because shipping a separate image for every possible PPI value isn't practical. Knowing which bucket a target device's PPI falls into tells a designer which image asset multiplier (1x, 1.5x, 2x, 3x, 4x) to export, without needing to reason about the exact PPI number every time.
Does a higher DPI bucket always mean a sharper-looking screen?
Generally yes for on-screen sharpness, but the bucket alone doesn't capture everything — viewing distance still matters (see the companion guide on Retina and viewing distance), and PPI² gives a better sense of area-based detail than PPI does on its own. Two phones in the same bucket can also have meaningfully different exact PPI, since buckets are ranges, not single values.
A note on this guide: Android density-bucket PPI ranges follow standard, widely published Android documentation conventions; exact cutoffs can vary slightly by source and Android version. Any specific numeric example (device PPI, PPI² comparisons) is illustrative for that exact scenario, not a universal constant. This content is informational and not a substitute for checking a device's actual published specifications.