How to Measure Screen Size and Dimensions

Step 1: Measure the Viewable Diagonal

Measure in a straight line from one viewable corner to the opposite viewable corner. Exclude the bezel, frame, and casing. The advertised product size usually refers to this diagonal rather than the width.

Step 2: Choose Inches or Centimeters

Enter the diagonal and select its unit. Changing the unit converts the draft value so the same physical size is preserved. The calculator reports results in both systems.

Step 3: Choose the Physical Aspect Ratio

Select a common ratio such as 16:9, 16:10, 21:9, 4:3, or 3:2. Choose Custom ratio for another proportional width and height. Use the panel specification rather than inferring the physical ratio from video content.

Step 4: Enter Native Resolution When Needed

Enter both horizontal and vertical pixel counts to calculate PPI, pixel pitch, diagonal pixels, and megapixels. Leave both blank when you only need physical dimensions. Display scaling and browser zoom do not change native pixel density.

Step 5: Read Physical Dimensions

The main result shows width and height in the selected unit. The metric cards also show converted dimensions and viewable rectangular area. These values exclude every part outside the active display.

Step 6: Read Pixel Measurements

• PPI: pixels per physical inch along the diagonal.
• Pixel pitch: approximate millimeters per pixel position.
• Megapixels: horizontal pixels multiplied by vertical pixels and divided by one million.
• Diagonal pixels: the pixel-grid hypotenuse.

Use the Dynamic Screen Diagram

The outline follows the entered aspect ratio and labels the diagonal when that ratio remains legible. It is not drawn at physical size. Extremely wide or tall custom ratios are fitted within a readable visual range; the adjacent measurement table and result cards always show the exact calculated values.

Review an Aspect-Ratio Mismatch Warning

If the resolution ratio differs from the physical ratio by more than 1%, verify both entries. A real device may have a rounded marketing ratio or cropped active area, but a mistaken entry can make the PPI assumption less useful.

Download the PDF Report

Select Download PDF to calculate the current draft values and save the entered diagonal, ratio, resolution, physical dimensions, area, and available pixel-density results.

What the Calculator Does Not Include

The result excludes bezels, frames, stands, device depth, curved-surface geometry, non-square pixels, subpixel layouts, software scaling, and viewing-distance recommendations. For a useful Screen Size Calculator result, use realistic inputs, compare relevant scenarios, and review the stated assumptions before making a decision.