Aspect Ratio Calculator

An aspect ratio describes the proportional relationship between the width and height of an image, video, screen or design. It is usually written as two numbers separated by a colon, such as 16:9, 4:3 or 1:1.

For example, an image measuring 1920 × 1080 pixels has a 16:9 aspect ratio. An image measuring 1280 × 720 has the same ratio despite having fewer pixels.

Maintaining the correct aspect ratio helps prevent images and videos from looking stretched or compressed when resized. Use the AabiTech Aspect Ratio Calculator to simplify dimensions and determine proportional sizes for your designs.

Use the Aspect Ratio Calculator to find the ratio of existing dimensions or determine a proportional width or height.

1. Enter the width of your image, video or design.
2. Enter its height.
3. Review the calculated aspect ratio.
4. Use a supported ratio preset when working with a standard format such as 16:9 or 1:1.
5. Use the ratio and a known dimension to determine the other dimension when supported by the calculator.

Check the resulting dimensions before exporting or publishing your design. If you also need to create a background for a design, try the CSS Gradient Generator.

To calculate a simplified aspect ratio, compare the width with the height and divide both values by their greatest common divisor (GCD).

For a 1920 × 1080 image, the GCD is 120. Dividing both dimensions by 120 gives 16 and 9, so the simplified aspect ratio is 16:9.

The formula is Width ÷ GCD : Height ÷ GCD. This method works with other positive whole-number dimensions and produces an exact simplified ratio.

For example, 1000 × 1000 simplifies to 1:1, while 1500 × 1000 simplifies to 3:2.

You can calculate a missing dimension when you know the aspect ratio and the other dimension. This is useful when resizing images, videos, thumbnails and graphics without changing their proportions.

For a 16:9 ratio with a width of 1920 pixels, calculate the height as follows:

Height = Width × 9 ÷ 16

Height = 1920 × 9 ÷ 16 = 1080 pixels

To calculate the width from a known height, use Width = Height × ratio width ÷ ratio height. If the result is fractional, round to a practical whole-pixel dimension and understand that rounding may slightly change the exact ratio.

To resize an image or video without distortion, scale its width and height by the same factor. This preserves the original width-to-height proportion.

For example, reducing a 1920 × 1080 image to 1280 pixels wide produces a height of 720 pixels, preserving its 16:9 ratio.

Changing only one dimension can stretch or compress the content. If the target frame has a different ratio, you may need to crop the image, add empty space around it or accept a different composition.

These principles are useful when preparing website images, video thumbnails, social graphics, presentations and responsive layouts.

Different types of digital content commonly use different aspect ratios. These examples are useful starting points, although the correct dimensions depend on the platform and project requirements.

• 16:9: widescreen video and many displays.
• 9:16: vertical video and mobile-oriented content.
• 1:1: square images and graphics.
• 4:3: traditional display and image formats.
• 3:2: a common photography format.
• 4:5: portrait-oriented social media graphics.
• 21:9: extra-wide cinematic displays and content.

Always check the destination platform requirements before exporting. The ratio alone does not determine image quality or pixel resolution.

Aspect ratio and resolution describe different properties of an image or video.

Aspect ratio describes the proportional relationship between width and height. For example, 16:9 describes a widescreen shape.

Resolution describes the actual pixel dimensions. For example, 1920 × 1080 is a resolution.

Two images can have different resolutions but share the same aspect ratio. Both 1280 × 720 and 1920 × 1080 are 16:9, but the second contains more pixels. More pixels do not automatically guarantee better visual quality because compression, source quality and display size also matter.

The basic aspect ratio compares the width with the height:

Aspect Ratio = Width : Height

To simplify the ratio, divide both dimensions by their greatest common divisor.

For example, 1280 × 720 gives 1280:720. The GCD is 80, so dividing both numbers by 80 produces 16:9.

For dimensions that cannot be reduced further, the simplified ratio may contain larger numbers. This exact ratio should not be confused with a familiar standard ratio that is only approximately equal.

Some image dimensions match a familiar aspect ratio exactly, while others are only close to it. This distinction matters when precise sizing is required.

For example, 1920 × 1080 simplifies exactly to 16:9. By contrast, 1366 × 768 simplifies to 683:384, which is close to 16:9 but not mathematically identical.

An exact simplified ratio preserves the precise relationship between the supplied dimensions. An approximate standard ratio can be convenient for everyday design work, but small differences may matter when matching technical specifications or calculating exact output dimensions.

Use these common dimension examples to understand how image sizes correspond to simplified aspect ratios.

These examples demonstrate that the same ratio can be used at different resolutions. Confirm the required dimensions and file specifications for your intended platform before publishing.