display aspect ratio calculator

Use the tools below to convert resolution to aspect ratio, calculate a missing dimension, and estimate physical screen width/height from diagonal size.

1) Resolution → Simplified Aspect Ratio

Display width (pixels)

Display height (pixels)

Enter width and height, then click "Calculate Ratio".

2) Ratio + One Dimension → Missing Dimension

Ratio width part

Ratio height part

Known dimension type

Known dimension value

Enter ratio and one dimension to find the other.

3) Diagonal Size + Ratio → Physical Width & Height

Diagonal size (inches)

Ratio width part

Ratio height part

Enter diagonal and ratio to get screen width/height in inches and centimeters.

What is a display aspect ratio?

A display aspect ratio is the proportional relationship between a screen's width and height. It is typically written as W:H (for example, 16:9), and it tells you the shape of the display rather than its exact pixel count.

Two displays can have very different resolutions but share the same aspect ratio. For instance, 1280×720 and 3840×2160 are both 16:9. One is lower resolution HD, and the other is 4K, but the shape is identical.

Why aspect ratio matters

Video compatibility: Most streaming media uses 16:9, while cinema formats can be wider.
Productivity: Ultrawide ratios like 21:9 give more horizontal space for timelines, spreadsheets, and multitasking.
Gaming experience: Some games support wider field-of-view at wider ratios.
Design/layout: UI and graphics can look stretched or letterboxed when ratio assumptions are wrong.

How this calculator helps

1) Convert resolution to a simplified ratio

Enter pixel width and height (for example, 2560 and 1440), and the tool simplifies the ratio (16:9). It also reports orientation (landscape, portrait, or square) and shows the decimal ratio.

2) Find a missing dimension

If you know the ratio and one side, you can calculate the other side instantly. This is useful when scaling videos, resizing images, or creating responsive layouts without distortion.

3) Convert diagonal size to physical width and height

People often buy screens by diagonal size alone, but that number does not tell you actual width and height. A 34" ultrawide and a 34" 16:9 monitor have very different usable shapes. This calculator gives both measurements directly.

Common display aspect ratios

4:3 — older monitors, classic TV content.
16:10 — productivity-focused displays with extra vertical space.
16:9 — modern standard for TVs, laptops, and most video platforms.
18:9 / 19.5:9 — common smartphone formats.
21:9 — ultrawide monitors and cinematic presentation.
32:9 — super ultrawide, effectively dual-monitor width in one panel.

Quick formula reference

Simplified ratio: divide width and height by their greatest common divisor.

Missing dimension: if ratio is A:B, then height = width × (B/A), and width = height × (A/B).

Physical dimensions from diagonal D and ratio A:B: width = D × A / √(A²+B²), height = D × B / √(A²+B²).

Final takeaway

Aspect ratio is one of the simplest but most important display specs. Use it whenever you compare monitors, scale media, build visual layouts, or optimize screen real estate. A few seconds of ratio math can save you from distortion, black bars, and costly hardware mismatches.