Screen Resolution Calculator
Last updated: June 2026
Formula
Diagonal pixels = square root of width pixels squared plus height pixels squared. PPI = diagonal pixels / screen size in inches.
| Screen | Resolution | PPI | Quality |
|---|---|---|---|
| 55in 4K | 3840 x 2160 | 80ppi | Standard |
| 27in 4K | 3840 x 2160 | 163ppi | Good |
| 13in FHD | 1920 x 1080 | 170ppi | Good |
| 6in FHD | 1920 x 1080 | 367ppi | Retina |
About this calculator
The Screen Resolution Calculator finds pixels per inch (PPI), total megapixels, and a simple sharpness category from screen size and resolution. It helps compare TVs, monitors, laptops, tablets, phones, and projectors.
PPI formula
PPI measures how many pixels fit into one inch of screen diagonal. Higher PPI usually looks sharper at the same viewing distance.
- diagonal pixels = sqrt(width_px² + height_px²)
- PPI = diagonal pixels / screen size inches
- megapixels = width_px x height_px / 1,000,000
How to use the screen resolution calculator
- Enter the screen diagonal size in inches.
- Choose a resolution preset or enter custom pixel dimensions.
- Review the PPI result.
- Check total megapixels.
- Compare the PPI with the quality guide and table.
Worked examples
55 inch 4K TV
Input: 55 inches, 3840 x 2160
Calculation: Diagonal pixels about 4,406. 4,406 / 55 = 80.
Result: About 80ppi, typical for a TV viewed from a distance.
27 inch 4K monitor
Input: 27 inches, 3840 x 2160
Calculation: 4,406 / 27 = 163.
Result: About 163ppi, much sharper at desk distance.
Why PPI depends on screen size
The same resolution looks sharper on a smaller screen because the pixels are packed more closely. A 4K phone-sized panel would have far higher PPI than a 55 inch TV.
PPI and viewing distance
TVs can have lower PPI than phones because you sit much farther away. For monitors and laptops, higher PPI is more noticeable because viewing distance is shorter.
Screen quality disclaimer
PPI is only one part of perceived quality. Brightness, contrast, HDR, panel type, motion handling, scaling, content quality, and viewing distance also matter.
Frequently asked questions
Is higher PPI always better?
Higher PPI is sharper, but the benefit depends on screen size, viewing distance, and whether content is high enough resolution.
Why does a 55 inch 4K TV have low PPI?
The same 4K pixels are spread over a large diagonal, but TVs are usually viewed from farther away.
What is retina quality?
It generally means pixels are dense enough that they are hard to distinguish at normal viewing distance.
Does PPI affect performance?
Resolution can affect device or gaming performance because more pixels require more rendering work. PPI itself is just a density measure.
What is megapixel count?
It is the total number of pixels on the screen, divided by one million.
Related calculators
- TV Size Calculator
- TV Dimensions Calculator
- Aspect Ratio Calculator
What does this mean?
This calculator is designed to help you understand the likely number before you make a decision or start an application.
Your result should be checked against official UK guidance, especially if your circumstances include dependants, exemptions, prior leave, or a complex immigration history.
Treat the figure as a planning tool rather than legal advice. Where the answer affects an application deadline or major payment, speak to an authorised adviser.
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