YouTube, Shorts, TikTok & Reels Aspect Ratio Calculator: Video Dimensions and Export Settings

Overview

An aspect ratio describes the relationship between a video's width and height. A 16:9 video is wide and is commonly used for standard YouTube videos, while a 9:16 video is vertical and designed for phone-first short-form platforms. The ratio is separate from resolution: 9:16 describes the shape, while 1080 × 1920 describes the number of pixels.

Use the following formats as practical starting points:

• 16:9 horizontal: 1920 × 1080 for standard HD video, or 3840 × 2160 for 4K projects.
• 9:16 vertical: 1080 × 1920 for Shorts, TikTok videos, Reels, and other mobile-first posts.
• 1:1 square: 1080 × 1080 when a square composition is specifically required.
• 4:5 portrait: 1080 × 1350 for a taller feed-oriented composition that is not as narrow as full-screen vertical video.
• 4:3: 1440 × 1080 or a similar proportional size for older footage, presentations, or intentionally classic-looking layouts.

These are production recommendations rather than permanent platform rules. Upload interfaces, display treatments, and maximum file specifications can change, so check the destination's current guidance when a project has unusual requirements. For most creators, however, matching the project to the intended viewing format is the most important decision.

How to estimate an aspect ratio

You can calculate a ratio from any pixel dimensions by dividing both numbers by their greatest common factor. For example, 1920 × 1080 becomes 16:9 after both dimensions are divided by 120. The same process turns 1080 × 1920 into 9:16.

To calculate a missing dimension, use a simple proportion:

Missing width = height × width ratio ÷ height ratio

Missing height = width × height ratio ÷ width ratio

For example, if you want a 16:9 canvas that is 1080 pixels high, calculate 1080 × 16 ÷ 9. The result is 1920 pixels wide. If you have a 1080-pixel-wide 9:16 canvas, calculate 1080 × 16 ÷ 9 to find a height of 1920 pixels.

An online aspect ratio calculator is useful when you are adapting footage that was recorded at an unusual size. Enter the original width and height first to identify its native ratio. Then enter the target ratio to estimate the new dimensions. Decide whether to crop, add padding, or place the original video inside a designed background. Cropping fills the frame but may remove important action; padding preserves the entire image but can make the result feel less native to the destination.

For a repeatable workflow, create one project template for each major output: a 16:9 YouTube template, a 9:16 short-form template, and a square or 4:5 template only if your publishing plan needs them. This is usually faster and more consistent than changing the canvas manually for every export.

Inputs and assumptions

The correct export depends on more than aspect ratio. Before editing, confirm these inputs:

1. Destination: Decide whether the file is for a standard YouTube upload, YouTube Shorts, TikTok, Instagram Reels, a feed post, or a website. A single master file may not suit every placement.
2. Source footage: Recordings made horizontally are not automatically suitable for vertical crops. Check where the subject, captions, product, or screen interface sits before committing to a crop.
3. Resolution: Use a project size that matches the intended output. Avoid enlarging low-resolution footage simply to reach a larger number; it cannot recreate detail that was not captured.
4. Frame rate: Match the source frame rate when practical. If you combine clips, choose deliberately rather than allowing every editing application to interpret the footage differently.
5. Codec and container: H.264 in an MP4 container is a broadly compatible starting point for many creator workflows. Your editor or destination may also support other formats for specific needs.
6. Bitrate: Treat bitrate as a quality-versus-file-size setting. A sensible 1080p starting range is often around 8–12 Mbps for ordinary web video, but fast motion, screen recordings, gradients, and detailed games may benefit from a higher setting. Test the result rather than assuming a larger file is always better.
7. Audio: Use a common compressed audio format and listen for clipping, background noise, and low dialogue before publishing. A clean soundtrack can matter more to perceived quality than a modest increase in video bitrate.

Keep text and important graphics away from the outer edges of vertical videos. Platform interfaces may place buttons, captions, or descriptions over parts of the image. The exact safe area varies by placement and can change, so preview the finished file on a phone before scheduling it.

Worked examples

Example 1: Turning a YouTube video into a Short

Suppose the original project is 1920 × 1080. A direct resize would make the video small inside a vertical canvas. Instead, create a 1080 × 1920 project and choose the most useful 9:16 crop from the horizontal footage. Reposition the subject, enlarge the shot only as far as quality allows, and rebuild captions so they remain readable. If the source contains a screen demonstration, consider using a cropped detail, a stacked layout, or a blurred duplicate background rather than shrinking the entire screen.

Example 2: Exporting one talking-head recording for several platforms

Record with enough space around the speaker if you expect to create both horizontal and vertical versions. Edit the long-form version in 16:9 at 1920 × 1080, then make a separate 9:16 sequence at 1080 × 1920. In the vertical version, adjust the crop manually for each important moment. Do not rely entirely on automatic reframing when the speaker moves, two people appear, or a product is held near the edge.

Example 3: Preserving a square graphic

If the source is 1080 × 1080, keep it square when the design depends on equal margins or a centered layout. Placing it in a 9:16 project can leave large unused areas. If you need a vertical post, redesign the composition for 1080 × 1920 instead of stretching the square file. Scaling preserves proportions; stretching changes the appearance of faces, logos, and type.

For broader workflow guidance, see our cross-posting workflow for Shorts, TikTok, and Reels. If editing speed is the constraint, compare video editing software built for faster creator workflows.

When to recalculate

Revisit your dimensions and export settings whenever the destination changes, the source camera changes, or the content format changes. A new phone, screen recorder, camera, or editing preset may produce different dimensions or frame rates. Recalculate before repurposing a horizontal livestream, webinar, or gameplay video into vertical clips, especially when captions and interface elements are central to the content.

Also check the project when a platform updates its upload guidance or your analytics show that viewers are struggling to read text. A technically correct ratio can still produce a poor viewing experience if subtitles are too small, the subject is cropped, or the visual hierarchy was designed for another screen shape.

Before exporting, use this short checklist:

• Confirm the destination and target aspect ratio.
• Set the canvas to the intended pixel dimensions.
• Review every crop, especially faces, products, and screen text.
• Keep key text clear of likely interface overlays.
• Match frame rate to the source where practical.
• Export a short test and watch it on the target device.
• Inspect the final file after upload rather than trusting the local preview alone.

Save the working dimensions, bitrate choice, and notes in your video workflow template. That turns the aspect ratio calculator from a one-time fix into a reusable publishing system. For adjacent production tools, explore free tools for content creators and the thumbnail contrast checker guide.