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TechnologyGenerated accuracy model review: 2026-05-06
PPI Calculator accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- PPI = √(w² + h²) / diagonal
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Horizontal Pixels: 1,920
- Vertical Pixels: 1,080
- Diagonal Size: 24 inch
Expected outputs
- Pixel Density: 92 PPI
- Total Megapixels: 2.07 MP
Known limitations
- This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
- Use the result as a planning estimate unless the calculator page states a stricter purpose.
Assumptions
- Width, height, and diagonal should all be positive values.
- PPI is calculated from the diagonal pixel count divided by the physical screen diagonal in inches.
- The displayed PPI is rounded to the nearest whole number.
Unit handling
- Horizontal Pixels accepts numeric values.
- Vertical Pixels accepts numeric values.
- Diagonal Size accepts values in inch.
- Pixel Density is displayed in PPI.
- Total Megapixels is displayed in MP.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current ppi-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for PPI Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.