Calculator inputs
Plotly graph
This chart shows how pixels per degree changes as distance increases.
Example data table
| Display | Screen Width (cm) | Screen Height (cm) | PPI | Pixel Pitch (mm) | 60 PPD Distance (cm) | 40 PPD Distance (cm) |
|---|---|---|---|---|---|---|
| 24" 1920 × 1080 | 53.1 | 29.9 | 91.79 | 0.277 | 95.1 | 63.4 |
| 27" 2560 × 1440 | 59.8 | 33.6 | 108.79 | 0.233 | 80.3 | 53.5 |
| 32" 3840 × 2160 | 70.8 | 39.8 | 137.68 | 0.184 | 63.4 | 42.3 |
| 65" 3840 × 2160 | 143.9 | 80.9 | 67.78 | 0.375 | 128.8 | 85.9 |
Formula used
1) Screen width and height from diagonal
width = diagonal × aspect width ÷ √(aspect width² + aspect height²)
height = diagonal × aspect height ÷ √(aspect width² + aspect height²)
2) Pixel density
PPI = √(resolution width² + resolution height²) ÷ diagonal
3) Pixel pitch
pixel pitch = 1 ÷ PPI
4) Single-pixel angular size
angle = 2 × arctan[(pixel pitch ÷ 2) ÷ viewing distance]
5) Pixels per degree
PPD = 1 ÷ pixel angle in degrees
6) Distance for a target sharpness level
distance = (pixel pitch ÷ 2) ÷ tan[(target angle in degrees ÷ 2)]
For a PPD target, target angle = 1 ÷ PPD degrees.
A common reference is 1 arcminute per pixel, which is close to 60 pixels per degree.
How to use this calculator
- Enter the screen diagonal and choose inches or centimeters.
- Type the display resolution, such as 1920 × 1080 or 3840 × 2160.
- Enter the aspect ratio, usually 16:9, 16:10, 21:9, or 4:3.
- Provide your real viewing distance and its unit.
- Set a visual acuity threshold in arcminutes. A value of 1 is a strong baseline.
- Choose a target PPD. Many users test around 40 to 60.
- Press Calculate to show results above the form, then review the graph and export options.
Frequently asked questions
1) What does pixel density mean?
Pixel density describes how many pixels fit into one inch of screen space. Higher values usually make text, icons, and edges look cleaner and more detailed at the same viewing distance.
2) What is viewing distance?
Viewing distance is the space between your eyes and the display. It strongly affects whether individual pixels are visible and how wide the screen feels in your field of view.
3) What is pixels per degree?
Pixels per degree measures how many screen pixels fit inside one degree of your vision. A higher PPD usually means smoother edges, finer text rendering, and less visible pixel structure.
4) Why is 60 PPD important?
Sixty PPD is often treated as a retina-like benchmark because one pixel then covers about one arcminute. Many people stop noticing individual pixels near that level, depending on eyesight and content.
5) Does higher PPI always mean a better screen?
Not always. A very dense display can still look unimpressive if you sit too far away, while a lower-density display may look fine when placed farther from your eyes.
6) Should I use the panel aspect ratio or the resolution ratio?
Use the physical panel aspect ratio. In most common displays it matches the resolution ratio, but custom rendering or letterboxing can make them differ in special cases.
7) Why does the calculator show field of view?
Field of view helps you understand immersion. Two screens can share the same PPI, yet the closer or larger one fills more of your vision and feels more cinematic.
8) Can I compare TVs, monitors, tablets, and phones here?
Yes. Enter each device’s diagonal, resolution, aspect ratio, and viewing distance. The calculator then normalizes them with PPI, pixel pitch, PPD, and recommended sharpness distances.