How to Calculate Aspect Ratio and Resize Video Without Distortion

Aspect ratio describes the proportional relationship between the width and height of an image or video. It determines whether the frame is widescreen, square, vertical, or another shape.

Common examples include:

• 16:9 for widescreen video
• 9:16 for vertical video
• 1:1 for square content
• 4:5 for portrait social media posts
• 4:3 for traditional television and older displays
• 21:9 for ultrawide and cinematic presentations

Aspect ratio is not the same as resolution. A 1280 × 720 video and a 3840 × 2160 video have very different pixel counts, but both use a 16:9 aspect ratio.

Maintaining the correct ratio is essential when resizing content. If the width or height is changed independently, people, objects, text, and graphics may appear stretched or compressed.

Use the Aspect Ratio Calculator to simplify a width and height, calculate a missing dimension, or resize an image or video proportionally.

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What Is Aspect Ratio?

Aspect ratio compares the width of a rectangular frame with its height.

It is written in the following format:

Width : Height

For example, a 16:9 frame is 16 proportional units wide for every 9 proportional units of height.

The numbers do not specify a particular resolution. They describe only the shape of the frame.

All of the following dimensions have a 16:9 aspect ratio:

• 640 × 360
• 1280 × 720
• 1920 × 1080
• 2560 × 1440
• 3840 × 2160
• 7680 × 4320

Each resolution contains a different number of pixels, but the proportional relationship between width and height remains the same.

A 9:16 frame reverses those proportions and creates a vertical format. Examples include 720 × 1280 and 1080 × 1920.

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Aspect Ratio vs. Resolution

Aspect ratio and resolution are related but separate concepts.

Aspect Ratio

Aspect ratio describes the shape of the frame.

Examples:

• 16:9
• 9:16
• 1:1
• 4:5
• 4:3

Resolution

Resolution describes the pixel dimensions.

Examples:

• 1280 × 720
• 1920 × 1080
• 1080 × 1920
• 1080 × 1350
• 3840 × 2160

Two files can have the same aspect ratio but different resolutions. Two files can also contain a similar number of pixels while using different aspect ratios.

For example:

• 1920 × 1080 is 16:9
• 1080 × 1920 is 9:16
• 1080 × 1080 is 1:1
• 1080 × 1350 is 4:5

The first two resolutions contain the same number of pixels, but their orientations are different.

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How to Calculate Aspect Ratio

To calculate an aspect ratio, divide both dimensions by their greatest common divisor.

The general process is:

1. Identify the width and height.
2. Find the greatest common divisor of those two numbers.
3. Divide both dimensions by that divisor.
4. Write the results as width to height.

Example: 1920 × 1080

The width is 1920, and the height is 1080.

The greatest common divisor is 120.

Divide both values:

1920 ÷ 120 = 16

1080 ÷ 120 = 9

The simplified aspect ratio is:

16:9

Example: 1080 × 1920

The greatest common divisor is again 120.

1080 ÷ 120 = 9

1920 ÷ 120 = 16

The aspect ratio is:

9:16

Example: 1080 × 1350

The greatest common divisor is 270.

1080 ÷ 270 = 4

1350 ÷ 270 = 5

The aspect ratio is:

4:5

Example: 1200 × 1200

Both values are identical.

1200 ÷ 1200 = 1

The aspect ratio is:

1:1

The Aspect Ratio Calculator can simplify these dimensions automatically.

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How to Calculate Aspect Ratio as a Decimal

Aspect ratios can also be represented as decimal values.

Divide the width by the height:

Decimal ratio = width ÷ height

Examples:

A ratio above 1 represents a frame that is wider than it is tall. A ratio below 1 represents a frame that is taller than it is wide.

Decimal ratios are useful when comparing dimensions that cannot be reduced into an immediately recognizable format.

For example:

1200 ÷ 628 = approximately 1.9108

This is commonly described as approximately 1.91:1.

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How to Calculate a Missing Height

If you know the target width and aspect ratio, calculate the height with this formula:

New height = new width × aspect height ÷ aspect width

For a 16:9 video with a width of 1920 pixels:

1920 × 9 ÷ 16 = 1080

The required height is 1080 pixels.

Example: 16:9 at 1280 Pixels Wide

1280 × 9 ÷ 16 = 720

The dimensions are:

1280 × 720

Example: 9:16 at 1080 Pixels Wide

1080 × 16 ÷ 9 = 1920

The dimensions are:

1080 × 1920

Example: 4:5 at 1080 Pixels Wide

1080 × 5 ÷ 4 = 1350

The dimensions are:

1080 × 1350

When the result is not a whole number, round to the nearest appropriate pixel. Some video encoders work best with even-numbered dimensions, so an odd result may need to be rounded to a nearby even number.

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How to Calculate a Missing Width

If the height and target aspect ratio are known, use:

New width = new height × aspect width ÷ aspect height

For a 16:9 video with a height of 1080 pixels:

1080 × 16 ÷ 9 = 1920

The required width is 1920 pixels.

Example: 9:16 at 1920 Pixels High

1920 × 9 ÷ 16 = 1080

The dimensions are:

1080 × 1920

Example: 4:5 at 1350 Pixels High

1350 × 4 ÷ 5 = 1080

The dimensions are:

1080 × 1350

Example: 1:1 at 1080 Pixels High

1080 × 1 ÷ 1 = 1080

The dimensions are:

1080 × 1080

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Common Aspect Ratios and Dimensions

The following dimensions maintain their stated ratios exactly unless otherwise noted.

A larger resolution does not change the ratio if the width and height are increased proportionally.

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Common 16:9 Dimensions

The 16:9 aspect ratio is widely used for television, desktop video, presentations, online video, and widescreen displays.

Common 16:9 sizes include:

The 854 × 480 format is a rounded practical dimension. An exact 16:9 width at 480 pixels high would be approximately 853.33 pixels, which is not possible as a normal whole-pixel frame.

This illustrates why some standard dimensions are close approximations rather than mathematically exact representations.

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Common 9:16 Dimensions

The 9:16 aspect ratio is the vertical version of 16:9. It is commonly used for full-screen mobile content.

Common dimensions include:

• 360 × 640
• 540 × 960
• 720 × 1280
• 1080 × 1920
• 1440 × 2560
• 2160 × 3840

A 1080 × 1920 canvas is a common starting point for vertical Full HD production.

Vertical interfaces may place captions, usernames, buttons, navigation controls, and other overlays near the edges. Keep important faces, product details, text, and logos away from the extreme top, bottom, and sides.

The full frame may technically be visible, but interface elements can cover important content.

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Common 1:1 Dimensions

A 1:1 aspect ratio is a perfect square. The width and height are identical.

Common square dimensions include:

• 640 × 640
• 720 × 720
• 1080 × 1080
• 1200 × 1200
• 2048 × 2048

Square content is useful when the same asset must work in feeds with limited horizontal or vertical space.

A square frame provides more vertical area than a 16:9 landscape frame but less vertical area than a 4:5 or 9:16 frame.

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Common 4:5 Dimensions

A 4:5 frame is a vertical format that is less tall than 9:16.

Common dimensions include:

• 640 × 800
• 720 × 900
• 1080 × 1350
• 1440 × 1800
• 2160 × 2700

The 1080 × 1350 format is widely used for portrait feed content.

A 4:5 composition can occupy more vertical screen area than a square post while avoiding the extreme height of full-screen vertical video.

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Common 4:3 Dimensions

The 4:3 ratio was widely used by traditional television, older computer displays, cameras, presentations, and archival footage.

Common dimensions include:

• 640 × 480
• 800 × 600
• 1024 × 768
• 1280 × 960
• 1440 × 1080
• 1600 × 1200

A 4:3 source displayed inside a 16:9 frame may produce vertical bars on the left and right. These are called pillarboxes.

Cropping the footage to fill 16:9 removes material from the top and bottom. The correct choice depends on whether filling the screen or preserving the complete original frame is more important.

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How to Resize Video Without Distortion

To resize a video without stretching, the width and height must change by the same scale factor.

The formula is:

Scale factor = new width ÷ original width

Then:

New height = original height × scale factor

Example: Resize 1920 × 1080 to 1280 Pixels Wide

Calculate the scale factor:

1280 ÷ 1920 = 0.6667

Apply the same factor to the height:

1080 × 0.6667 = 720

The proportional result is:

1280 × 720

Both dimensions were reduced to approximately 66.67% of their original values. The 16:9 aspect ratio was preserved.

Incorrect Resize

Changing 1920 × 1080 into 1280 × 800 changes the shape of the frame.

• Original ratio: 16:9, or approximately 1.7778
• New ratio: 1280 ÷ 800 = 1.6

If the image is forced into the new dimensions without cropping or padding, it will be distorted.

Correct Alternatives

To place 16:9 content into a differently shaped frame, use one of the following:

• Crop part of the image
• Add padding
• Reframe the composition
• Use a blurred or designed background
• Change the canvas while keeping the video layer proportional

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Scaling, Cropping, Padding, and Stretching

These four operations produce different results.

Scaling

Scaling changes the physical dimensions while preserving the aspect ratio.

Example:

1920 × 1080 → 1280 × 720

Nothing is cropped, and the image is not distorted.

Cropping

Cropping removes part of the image so that the remaining content fills a different frame shape.

Example:

1920 × 1080 → 1080 × 1080

If the full source height is preserved, 840 pixels must be removed from both the left and right sides combined. A centered crop removes approximately 420 pixels from each side.

The resulting image fills the square frame without stretching, but some content is lost.

Padding

Padding preserves the complete image and adds empty space around it.

The added area may appear as:

• Black bars
• White bars
• A solid brand color
• A blurred copy of the video
• A graphic background
• Additional text or design elements

No original content is removed, but the video does not fill the entire target frame.

Stretching

Stretching changes the width and height independently to force the source into a new shape.

This distorts the image. Circles may become ovals, and people may appear unusually wide or narrow.

Stretching should generally be avoided.

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How to Crop 16:9 Video to 1:1

Suppose the source is 1920 × 1080 and the target is square.

If the full height of 1080 pixels is retained, the target width must also be 1080 pixels.

The crop is:

1920 − 1080 = 840 pixels

For a centered crop:

840 ÷ 2 = 420 pixels

Remove approximately:

• 420 pixels from the left
• 420 pixels from the right

The result is:

1080 × 1080

This method works well when the subject is near the center. If the subject moves across the original frame, keyframed reframing may be required.

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How to Crop 16:9 Video to 4:5

Suppose the source is 1920 × 1080 and the target is 4:5.

Using the complete source height:

Target width = 1080 × 4 ÷ 5

Target width = 864 pixels

The total horizontal crop is:

1920 − 864 = 1056 pixels

For a centered crop:

1056 ÷ 2 = 528 pixels

Remove approximately 528 pixels from each side to create an 864 × 1080 crop.

The cropped result can then be scaled to 1080 × 1350 for a standard portrait canvas.

A centered crop may remove important content from a wide shot. Review every scene instead of applying one fixed crop to an entire video without inspection.

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How to Crop 16:9 Video to 9:16

Converting landscape video to full-screen vertical video requires a substantial crop.

Using a 1920 × 1080 source and preserving its full height:

Target width = 1080 × 9 ÷ 16

Target width = 607.5 pixels

Since video dimensions normally use whole pixels, the practical crop width may be rounded to approximately 608 pixels.

The total horizontal removal is approximately:

1920 − 608 = 1312 pixels

For a centered crop, approximately 656 pixels are removed from each side.

Only about one-third of the original horizontal frame remains. This can easily remove people, text, products, gameplay elements, or visual context.

For reliable horizontal-to-vertical conversion:

• Keep the main subject near the center while recording
• Record at a sufficiently high resolution
• Reposition the crop for each shot
• Use automated tracking carefully
• Move captions and graphics into the vertical safe area
• Review the final video on a phone-sized display

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What Are Letterboxing and Pillarboxing?

Letterboxing and pillarboxing preserve the original aspect ratio by adding unused space.

Letterboxing

Letterboxing adds horizontal bars above and below the image.

This occurs when a wide video is placed inside a relatively taller or narrower frame.

For example, cinematic footage displayed in a 16:9 player may have bars at the top and bottom.

Pillarboxing

Pillarboxing adds vertical bars to the left and right.

This commonly occurs when 4:3 footage is displayed in a 16:9 frame.

Windowboxing

Windowboxing adds space on all four sides. It can happen when media already containing bars is placed inside another mismatched frame.

Avoid permanently encoding unnecessary bars into the source file when the destination player can adapt to the video’s native ratio. YouTube’s player adjusts to different aspect ratios and devices, so manually adding padding is not always necessary.

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Display Aspect Ratio vs. Pixel Aspect Ratio

Most modern online video uses square pixels, meaning each pixel has a pixel aspect ratio of 1:1.

However, some older broadcast and standard-definition formats use non-square pixels. In those cases, the stored pixel dimensions do not directly describe the final displayed shape.

Three related concepts may appear in editing software:

Storage Aspect Ratio

The ratio of the stored pixel dimensions.

Pixel Aspect Ratio

The proportional shape of each individual pixel.

Display Aspect Ratio

The shape in which the video is intended to appear during playback.

For most modern HD, UHD, web, and social media workflows, square pixels simplify the relationship:

Display aspect ratio = width ÷ height

When working with anamorphic, archival, DVD, or older broadcast footage, confirm the pixel aspect ratio before resizing.

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Choosing an Aspect Ratio for YouTube

YouTube’s standard aspect ratio on computers is 16:9. The player can also adapt to vertical, square, and other video shapes.

Common YouTube dimensions include:

YouTube advises creators not to add padding or black bars directly to a video merely to force it into a 16:9 frame. The player can adjust to the uploaded aspect ratio.

Videos that qualify for YouTube Shorts can use square or vertical formats. Current Shorts classification and duration rules may change, so check YouTube’s official documentation before building a time-sensitive publishing workflow.

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Choosing an Aspect Ratio for Instagram and Meta Placements

Meta supports multiple ratios across Instagram and Facebook placements. The best choice depends on whether the content appears in a feed, Story, Reel, or advertisement.

Common production formats include:

Meta recommends vertical formats for placements designed to fill a phone screen. For Stories, a 9:16 canvas at 1080 × 1920 is a common production size.

Do not place important text or logos against the edges. Interface elements can overlap the creative even when the file itself uses the correct dimensions.

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Choosing an Aspect Ratio for TikTok

TikTok is primarily designed around vertical mobile viewing. A 9:16 frame is generally the preferred format for full-screen content.

Common TikTok creative formats include:

• 9:16 vertical
• 1:1 square
• 16:9 horizontal

Example production dimensions include:

• 1080 × 1920 for 9:16
• 1080 × 1080 for 1:1
• 1920 × 1080 for 16:9

TikTok’s advertising specifications vary by format and placement. Some documented formats have different minimum dimensions, file limits, and duration requirements.

Before producing an advertisement, check the exact specification for the selected campaign format instead of relying on a general organic-video recommendation.

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Choosing an Aspect Ratio for LinkedIn

LinkedIn accepts a range of landscape, square, and vertical video ratios.

Common creative formats include:

LinkedIn’s general video documentation supports ratios across a broad range, while advertising formats provide more specific recommended dimensions.

LinkedIn also recommends keeping important elements away from the edges because interface overlays may cover text, logos, or other content.

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How to Create One Video for Multiple Aspect Ratios

A single edit rarely fits every destination perfectly.

A better workflow is to create a master composition and produce platform-specific versions.

Start with the Highest Useful Resolution

A high-resolution source provides more room for cropping and reframing.

For example, a 4K landscape source gives more flexibility than a low-resolution 720p source when extracting a vertical crop.

Higher resolution does not solve poor composition, but it helps preserve detail after cropping.

Protect the Center of the Frame

If a horizontal video will later become vertical, keep critical subjects within a central protected area.

Important elements include:

• Faces
• Products
• Demonstrations
• Captions
• Logos
• Calls to action
• Interface controls
• Gameplay information

Separate Text from the Original Footage

Add captions and graphics as editable layers rather than permanently embedding them in the source footage.

This allows each version to use a different position, size, and line length.

Reframe Each Shot

Do not assume one crop position will work for the whole video. The subject may move from left to right, or different shots may use different compositions.

Adjust the framing shot by shot.

Review Every Output

Check the actual exported versions:

• 16:9 landscape
• 1:1 square
• 4:5 portrait
• 9:16 vertical

Look for cropped faces, hidden captions, small text, empty space, interface overlap, and unintended distortion.

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Does Changing Aspect Ratio Affect File Size?

Changing aspect ratio can affect file size indirectly.

If the new dimensions contain fewer pixels, the encoder may require less data. However, bitrate and duration remain the main factors in calculating compressed file size.

For example:

• 1920 × 1080 contains 2,073,600 pixels
• 1080 × 1080 contains 1,166,400 pixels
• 1080 × 1350 contains 1,458,000 pixels
• 1080 × 1920 contains 2,073,600 pixels

A 1920 × 1080 file and a 1080 × 1920 file contain the same number of pixels per frame, although their orientations differ.

Files with the same pixel count can still have different sizes if they use different:

• Bitrates
• Codecs
• Frame rates
• Audio settings
• Durations
• Compression modes
• Visual content

Use the Video File Size Calculator to estimate storage from bitrate and duration.

For additional examples, read How Much Storage Does Video Use? File Size by Resolution and Duration.

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Does Changing Aspect Ratio Affect Video Bitrate?

Aspect ratio does not automatically define the required bitrate.

However, changing the dimensions can alter:

• The number of pixels per frame
• The amount of visible detail
• The complexity of the composition
• The destination platform
• The recommended export settings

A high-resolution vertical video may require more bitrate than a low-resolution horizontal video. Orientation alone is not enough to choose a bitrate.

Read What Video Bitrate Should You Use for 1080p, 1440p, and 4K? for resolution, frame-rate, codec, and upload recommendations.

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Common Aspect Ratio Mistakes

Changing Only One Dimension

Changing the width without calculating the corresponding height alters the ratio and distorts the image.

Forcing Every Video into 16:9

Modern platforms can support multiple aspect ratios. A vertical or square source does not always need to be placed inside a 16:9 frame.

Adding Permanent Black Bars

Manually adding bars may create unnecessary padding when the player can adapt to the source ratio.

Applying One Center Crop to Every Shot

A fixed crop may work for one scene but remove the subject in another. Review and reposition the crop throughout the edit.

Confusing 4:5 with 5:4

A 4:5 frame is vertical because the width is smaller than the height. A 5:4 frame is horizontal.

Confusing 16:9 with 9:16

The first number represents width, and the second represents height.

• 16:9 is horizontal
• 9:16 is vertical

Using Approximate Dimensions Without Checking

Some published dimensions are rounded approximations. Calculate the actual decimal ratio when precise matching matters.

Ignoring Safe Areas

A technically correct frame can still have captions or logos covered by platform controls. Keep essential content away from the edges.

Upscaling Without a Reason

Increasing a small file to a larger resolution does not restore missing detail. It only creates more pixels from the existing image.

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Frequently Asked Questions

What aspect ratio is 1920 × 1080?

1920 × 1080 simplifies to 16:9.

What aspect ratio is 1080 × 1920?

1080 × 1920 simplifies to 9:16.

What aspect ratio is 1080 × 1350?

1080 × 1350 simplifies to 4:5.

What aspect ratio is 1080 × 1080?

It is 1:1, or square.

What aspect ratio is 1280 × 720?

1280 × 720 simplifies to 16:9.

How do I find height from width?

Multiply the new width by the ratio’s height value, then divide by its width value.

For 16:9:

Height = width × 9 ÷ 16

How do I find width from height?

Multiply the new height by the ratio’s width value, then divide by its height value.

For 16:9:

Width = height × 16 ÷ 9

Can I change aspect ratio without cropping?

Yes. You can preserve the complete image by adding padding or placing the source over a designed background. The video will not fill the entire target frame.

Can I change aspect ratio without black bars?

Yes, but you must either crop the source, reframe it, extend the background, or redesign the composition. Filling a different frame without cropping, padding, or distortion is not always geometrically possible.

What is the best aspect ratio for YouTube?

The standard YouTube aspect ratio on computers is 16:9. YouTube also supports and adapts to square, vertical, and other aspect ratios.

What is the best aspect ratio for vertical video?

A 9:16 ratio is commonly used for full-screen vertical video. A typical Full HD size is 1080 × 1920.

Is resolution the same as aspect ratio?

No. Resolution specifies pixel dimensions, while aspect ratio describes the proportional shape of those dimensions.

Does cropping reduce video quality?

Cropping removes pixels from the original frame. If the remaining crop must be enlarged significantly, the output may appear softer. Starting with a higher-resolution source provides more flexibility.

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Final Recommendations

To resize a video without distortion:

1. Identify the original width and height.
2. Calculate or simplify the original aspect ratio.
3. Choose the required target ratio.
4. Calculate the missing width or height.
5. Scale both dimensions proportionally.
6. Use cropping or padding when the target shape differs.
7. Avoid independent horizontal or vertical stretching.
8. Reframe important subjects for each output.
9. Keep text and logos inside a safe central area.
10. Review the exported file on the intended device.

Use the Aspect Ratio Calculator to simplify dimensions and calculate a proportional resize.

For related production planning, use the Video Bitrate Calculator and Video File Size Calculator.

Correct dimensions prevent distortion, but good reframing requires more than mathematics. The final composition must also preserve the subject, visual hierarchy, readable text, and platform-safe placement.