Screen Size Calculator

How the Screen Size Calculator Works

The Screen Size Calculator is a powerful tool that helps you determine the exact width, height, and area of a screen based on its diagonal and aspect ratio. Whether you're dealing with a TV, monitor, smartphone, or tablet, it provides precise dimensions crucial for comparing devices and planning installations.

This calculator is widely used by electronics buyers, audiovisual professionals, technicians, and designers. It ensures that every screen fits correctly in a setup, meets technical requirements, or matches aesthetic expectations in commercial and personal projects.

Screen Size Calculation Formula

The main formula is based on the Pythagorean theorem. When you know the diagonal (D) and aspect ratio (W:H), you can calculate width and height using:

• Width = D × (W / √(W² + H²))

• Height = D × (H / √(W² + H²))

• Area = Width × Height

For a 30 cm diagonal screen with a 16:9 aspect ratio:

• Width ≈ 26.15 cm

• Height ≈ 14.71 cm

• Area ≈ 384.57 cm²

These calculations provide the true visible size of the screen, not just its diagonal.

Example Calculations for Common Screen Sizes

Here are a few real-world examples using the Screen Size Calculator:

• 24-inch monitor, 16:9 ratio
  Width ≈ 53.14 cm
  Height ≈ 29.89 cm
  Area ≈ 1588.84 cm²

• 55-inch TV, 16:9 ratio
  Width ≈ 121.76 cm
  Height ≈ 68.45 cm
  Area ≈ 8328.13 cm²

• 13.3-inch laptop, 16:10 ratio
  Width ≈ 28.26 cm
  Height ≈ 17.66 cm
  Area ≈ 499.19 cm²

These dimensions help buyers understand physical size, beyond the diagonal.

Why is it important to know the exact screen dimensions?

Knowing the true dimensions of a screen is critical for accurate installations, especially in environments with limited space. For example, wall mounts, built-in cabinets, or desktop stands must match both width and height—not just diagonal.

Also, for visual planning, such as in UI/UX design or digital signage, screen dimensions affect layout, spacing, and resolution density. It’s also helpful for comparing screens with different aspect ratios side by side.

Can this calculator be used for curved screens?

Yes, the Screen Size Calculator supports curved screens as well. When selected, it factors in the screen's curvature, radius, and depth. This ensures the width and height values reflect the screen’s physical dimensions, accounting for its 3D shape.

Curved screens are common in gaming, cinematic displays, and ergonomic workstations, where the visual experience depends on screen shape. Exact measurements ensure optimal positioning and installation.

What’s the difference between diagonal and actual size?

The diagonal is the most advertised measurement but doesn’t give the full picture. Two screens with the same diagonal can have different widths and heights if their aspect ratios differ.

For example:

• A 30 cm diagonal screen with 16:9 ratio is 26.15 × 14.71 cm

• The same diagonal with 4:3 ratio becomes 24.00 × 18.00 cm

That’s why relying only on diagonal can lead to misjudging fit or visual area.

Common Screen Dimensions Table

Here’s a quick table of standard diagonal sizes and their dimensions for 16:9 screens:

Values may slightly vary depending on decimal rounding.

Practical Uses for Designers and Installers

• Interior design: Ensuring a TV or monitor fits on a wall or into cabinetry.

• UX/UI design: Simulating how apps or interfaces look on actual devices.

• Retail planning: Setting up screens in display walls or digital kiosks.

• Theater rooms: Positioning large curved screens for optimal viewing angles.

With exact dimensions, you can avoid last-minute surprises and redesigns.

Is it useful for buying new devices?

Definitely. When buying a new monitor, TV, or phone, the diagonal isn’t always enough. The calculator helps compare devices with different aspect ratios or determine whether a larger screen actually means more viewing area.

It also supports smarter decisions when switching from one device to another or upgrading a workspace setup.