Screen Size Calculator
Convert a display diagonal and aspect ratio into physical width, height, and screen area, with optional curved-screen footprint measurements.
Display inputs
Live results
Screen area
14.37 in²
Rectangular viewable area implied by the diagonal and aspect ratio.
Dimension detail
| Metric | Value | What it represents |
|---|---|---|
| Diagonal | 5.80 in | Corner-to-corner viewable display measure. |
| Width | 5.06 in | Horizontal physical span for the selected aspect ratio. |
| Height | 2.84 in | Vertical physical span for the selected aspect ratio. |
| Screen area | 14.37 in² | Rectangular width multiplied by height. |
Curved mode keeps the screen surface width as an arc length and adds the straight base width and center depth of that arc.
How to use this screen size calculator
What this calculator does. This tool translates a rectangular display's diagonal and aspect ratio into physical width, height, and viewable screen area. In Curved mode it also estimates the straight chord across the curved face, labeled Base width, and the center-to-chord offset, labeled Base depth, from the stated curvature radius. It is a geometry calculator, not a viewing-distance, image-resolution, bezel-size, brightness, or ergonomics recommendation. The aspect-ratio convention used here is width divided by height, consistent with the W3C definition of a width/height aspect ratio.
When to use it. It is useful when checking whether a TV or monitor will fit a cabinet or wall opening, comparing two phones whose diagonals use different aspect ratios, converting an advertised diagonal into actual width and height, or estimating how far a curved monitor projects forward from the chord joining its left and right edges.
How to calculate. The calculator opens with a ready-to-use 5.8-inch, 16:9 flat-screen demonstration and an immediately available XLSX export. To replace it:
- Choose Screen type. Flat uses ordinary rectangle geometry. Curved adds curvature calculations while keeping the surface width implied by diagonal and aspect ratio.
- Choose Aspect ratio. For an uncommon format choose Custom, then enter Custom ratio width and Custom ratio height.
- Enter Diagonal and choose the Length unit. Unit changes convert the current diagonal rather than merely relabeling it.
- For Curved mode, enter Curvature radius in millimeters; for example, type 1800 for a display marketed as 1800R.
- Read the live result cards and Dimension detail table, then use Download Excel to export the current typed inputs and calculated outputs. Reset clears the demonstration/input data; Excel export is then disabled until a complete valid state is entered again.
Input guide. Screen type is required and accepts Flat or Curved; switching to Curved exposes the radius field and adds footprint results. Aspect ratio is required and offers common width:height presets plus Custom. A larger width-to-height ratio makes a fixed-diagonal screen wider and shorter. Custom ratio width and Custom ratio height are positive decimal numbers required only for Custom; 2.17 and 1 is a realistic phone example. Do not enter a colon in either custom field. Diagonal is required, must be a positive finite decimal, and accepts standard en-US grouping such as 1,234.5; decimal commas and scientific notation are rejected rather than reinterpreted. A larger diagonal scales width and height linearly and area quadratically. Length unit is required and supports inches, centimeters, and millimeters. The calculator uses exact metric relationships; NIST states that one inch equals exactly 25.4 millimeters. Curvature radius is required only in Curved mode, is entered as a positive finite number in millimeters, and typically appears in product specifications as 1000R, 1500R, 1800R, and similar notation. A smaller radius means stronger curvature, generally reducing Base width and increasing Base depth for the same surface width.
Output guide. Screen area is the rectangular surface area implied by width × height and is shown in square units; it is an exact geometric consequence of the entered values, not a usable-pixel-area estimate. Width and Height are physical surface dimensions in the selected length unit. Diagonal echoes the normalized input in that unit, and Aspect ratio shows the active width:height definition. The live header pills for Mode, Area, Width, and Height repeat the same canonical results for quick scanning. In Curved mode, Base width is the straight chord between the left and right screen edges, while Base depth is the sagitta from that chord to the midpoint of the screen arc. Both are estimates under the circular-arc model. In the Dimension detail table, the Metric column names each active result, the Value column shows its formatted measurement, and the What it represents column explains the geometry; the table is not a separate calculation.
Worked example. With the startup values Diagonal = 5.8 in and Aspect ratio = 16:9, the ratio is 16/9 ≈ 1.7778. Height is 5.8 ÷ √((16/9)² + 1) = 2.8435 in. Width is (16/9) × 2.8435 = 5.0551 in. Area is 5.0551 × 2.8435 = 14.3744 in². Rounded for display, the first-open results are 2.84 in high, 5.06 in wide, and 14.37 in², matching the values exported to the workbook at full numeric precision.
Learn more. For industry context, the Society for Information Display's measurement standard includes sections on display size, viewable area, and aspect ratio. These concepts explain why two displays with the same diagonal can have different widths, heights, and surface areas.
How the geometry works
A screen diagonal is the hypotenuse of a right triangle whose legs are the screen's width and height. If the aspect ratio is r = width ÷ height, substituting width = r × height into the Pythagorean relationship produces the direct formulas used by the calculator.
width = r × height
area = width × height
For curved displays, the calculated surface width is treated as circular arc length. With radius R and arc length L, the half-angle is L ÷ (2R). The straight chord is 2R × sin(L ÷ (2R)), and the center depth is R × (1 – cos(L ÷ (2R))). This idealized circular-arc model does not account for bezels, nonuniform panel curvature, cutouts, rounded corners, or casing thickness.
Interpreting diagonal claims
A diagonal by itself does not determine a display's width or area. At a fixed diagonal, a wider aspect ratio spreads the same corner-to-corner distance across more horizontal span and less vertical span. That is why comparing products only by diagonal can be misleading when their proportions differ. For physical fit checks, use the calculated Width and Height and then add the manufacturer's bezel or enclosure dimensions separately.