Screen PPI From Diagonal Resolution
Physical diagonal PPI from actual raster and physical panel diagonal, not CSS96 ppi or device pixel ratio. Explicit caller font/layout/reference context; not a shaping engine, actual page layout or accessibility certification.
Description
Physical screen PPI measures raster pixels per physical inch.
Physical screen PPI measures raster pixels per physical inch.1
It is distinct from a CSS pixel scale or the ratio between device and CSS pixels.
When to use Screen PPI From Diagonal Resolution
Use this tool when you need to reproduce the stated calculation from measured records or independently selected model inputs. Establish the font version, feature, layout, physical or CSS units, and matched reference basis needed for this calculation.
How to use Screen PPI From Diagonal Resolution and understand its results
- Establish the font version, feature, layout, physical or CSS units, and matched reference basis needed for this calculation.
- Enter pixelWidth, pixelHeight, physicalDiagonalInches, following the field table and rules below, then run the tool.
- Read physicalPixelsPerInch. Use the output meanings below to interpret units, signs, flags, and any nested result fields.
- Correct reported input issues and run again. For a successful result, check the stated evidence coverage and assumptions before using it in your review.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| pixelWidth | Pixel width | number | Required |
| pixelHeight | Pixel height | number | Required |
| physicalDiagonalInches | Physical diagonal inches | number | Required |
Use integer pixel width and height from one to one million and a positive physical diagonal in inches. Divide the raster diagonal, calculated with the hypotenuse, by the physical diagonal.
PPI=√(pixelWidth²+pixelHeight²)/diagonalInches Symbols follow the input and output meanings and the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| physicalPixelsPerInch | Physical pixels per inch | number |
{
"input": {
"pixelWidth": 1920,
"pixelHeight": 1080,
"physicalDiagonalInches": 24
},
"output": {
"physicalPixelsPerInch": 91.7877987534291
}
}Limitations and assumptions
The calculation uses declared units and font or layout assumptions. It does not shape glyphs, lay out actual pages, or certify accessibility or print quality.
Missing required fields, unknown fields, wrong types, and violated calculation rules are input issues. Numeric values must be finite; nonfinite results are rejected.
Alternative or Complementary methods
For a related review, use Device Pixel Ratio CSS px Lookup: Device pixel ratio compares matched device-pixel and CSS-pixel extents. It describes that observation rather than a physical pixels-per-inch measurement or a fixed value for a device name. For a complementary step, use Print Size From Image Resolution: A raster’s print dimensions follow from its pixel dimensions and a chosen pixels-per-inch density. Both axes matter when planning a print.
References
-
Screen PPI From Diagonal Resolution — tool.io
Similar or alternative tools
- Device Pixel Ratio CSS px Lookup
Device pixel ratio compares matched device-pixel and CSS-pixel extents. It describes that observation rather than a physical pixels-per-inch measurement or a fixed value for a device name.
- Print Size From Image Resolution
A raster’s print dimensions follow from its pixel dimensions and a chosen pixels-per-inch density. Both axes matter when planning a print.