Screen Size Calculator
Calculate diagonal screen size and PPI from width and height in pixels.
Screen size calculator
Enter the diagonal size and resolution to calculate physical width, height, aspect ratio, PPI, megapixels, and pixel pitch.
Aspect ratio can be detected from the resolution or selected manually.
Physical display size
20.9″ × 11.8″
53.1 cm × 29.9 cm
Pixel density
91.8 PPI
Pixels per inch.
Diagonal
24.0″
61.0 cm.
Display results dashboard
Resolution
1920 × 1080
Full HD
Aspect ratio
16:9
Resolution simplifies to 16:9.
Total pixels
2,073,600
2.07 megapixels.
Pixel pitch
0.277 mm
Approximate distance between pixels.
Preset devices
Load common display examples instantly.
Local calculation
All display size and PPI calculations run locally in the browser.
Display comparison
Compare monitors, laptops, phones, tablets, and TVs with consistent math.
Copy-ready results
Copy physical size, aspect ratio, PPI, megapixels, and pixel pitch.
Dynamic Screen Insights
How Screen Size Calculation Works
Diagonal size
Screen size is usually measured corner to corner.
Aspect ratio
Aspect ratio describes proportional width and height.
Resolution
Resolution describes pixel width and height.
Physical size
Width and height come from diagonal size and ratio.
PPI
PPI comes from diagonal pixels divided by diagonal inches.
Diagonal Size, Aspect Ratio, Width, and Height Explained
Diagonal
The corner-to-corner display measurement.
Aspect ratio
The shape of the screen, such as 16:9 or 16:10.
16:9
Common for TVs and many monitors.
16:10 and 3:2
Common on some laptops and tablets.
21:9
Common for ultrawide monitors.
Same diagonal, different shape
Two displays can share a diagonal but have different width and height.
Resolution, PPI, CSS Pixels, and Physical Size Notes
Resolution
The number of pixels across and down.
PPI
Pixel density, or pixels per inch.
Physical size
Higher resolution does not always mean a physically larger screen.
CSS pixels
CSS pixels can differ from physical pixels on high-DPI devices.
Viewport size
Browser viewport size is different from physical screen size.
Scaling
Operating system scaling affects how large UI appears.
Common Screen Size Examples
13.3-inch laptop
2560 × 1600
15.6-inch laptop
1920 × 1080
24-inch monitor
1920 × 1080
27-inch monitor
2560 × 1440
32-inch monitor
3840 × 2160
55-inch TV
3840 × 2160
Phone screen
High PPI display
Tablet screen
4:3 or 3:2 ratio
Design, Device, and Display Use Cases
Formula / Method Explanation
Aspect ratio = width pixels : height pixels
Diagonal pixels = √(width pixels² + height pixels²)
PPI = diagonal pixels ÷ diagonal inches
Physical width = diagonal inches × aspect width ÷ √(aspect width² + aspect height²)
Physical height = diagonal inches × aspect height ÷ √(aspect width² + aspect height²)
Total pixels = width pixels × height pixels
Megapixels = total pixels ÷ 1,000,000
Pixel pitch in mm = 25.4 ÷ PPIFrequently Asked Questions
Related tools