Screen / Physical size
Screen Size Calculator: Physical Dimensions and Comparison
Enter two screen diagonals and aspect ratios or resolutions to compare their physical width, height and area. Resolution inputs also show PPI.
Screen Size Calculator: Physical Dimensions and Comparison: Uses the diagonal and shape to find the visible rectangle's dimensions, excluding bezel and stand. Both screens share a drawing scale so size differences remain visible. Shows width and height in centimetres and inches, area in square units, and the ratio between areas. With resolution input, shows pixel density too. Runs 100% locally in your browser with zero server file uploads.
- Category
- Everyday tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Relative physical scale; the drawing is not actual size on your device.
Screen 1
Screen 2
Screen 2 has 140.5% of screen 1's area.
Use the visible screen diagonal, excluding the bezel. Width = diagonal × ratio width / √(ratio width² + ratio height²); height uses ratio height. Area = width × height. One inch = 2.54 cm. Resolution sets both the shape and PPI = √(horizontal pixels² + vertical pixels²) / diagonal in inches.
Screen PPI and dot pitch · Aspect ratio calculator · Monitor and dead-pixel test
Rectangle geometry
For ratio a:b and diagonal D, width = D × a / √(a² + b²), height = D × b / √(a² + b²), and area = width × height. For resolution H × V, PPI = √(H² + V²) / diagonal in inches. These are Pythagorean geometry calculations for a rectangular screen.
Units and assumptions
The international inch is exactly 2.54 cm. Square-inch area converts by multiplying by 2.54². NIST SI unit guidance: https://www.nist.gov/pml/special-publication-811 . Diagonal excludes housing; resolution mode assumes the displayed rectangle has the same shape as the pixel grid.
How to use it
- Enter each visible screen's diagonal in inches.
- Choose aspect ratio or resolution and enter the two dimensions.
- Compare the same-scale drawing, dimensions, areas and optional PPI.
Privacy & limitations
Your screen inputs are calculated locally in the browser.
Related tools
Frequently asked questions
Is the picture actual size?
No. It compares the two screens at one shared scale and fits your browser. Use Online Ruler for a calibrated on-screen ruler.
Does diagonal alone tell me the width?
No. Aspect ratio matters: a 4:3 and a 16:9 screen with the same diagonal have different widths, heights and areas.
How is this different from the PPI calculator?
This page starts with two physical screens and compares area and dimensions. Screen PPI Calculator focuses on density and dot pitch.
Free tool · runs in your browser · no account required