What aspect ratio means and why you'd change it
Aspect ratio is the relationship between the width and height of an image, video, or canvas — written as two numbers like 16:9 or 4:3. You change it when the content you're making needs to fit a different screen, platform, or print size. A video shot in 16:9 (widescreen) won't fill a square Instagram post without black bars or cropping. A photo taken on your phone might be 9:16 (portrait) but your website template expects 16:9 (landscape).
The method for changing aspect ratio depends entirely on what software you're using — video editors, image editors, and design tools all handle it differently. This guide covers the most common programs you'll encounter and the exact steps to change the ratio in each one.
Key Takeaways
- Aspect ratio is the width-to-height proportion of your image or video, and different platforms require different ratios.
- Most software lets you change aspect ratio by resizing the canvas or frame, not by stretching the content itself.
- Video editors like DaVinci Resolve and Adobe Premiere Pro change ratio in the project settings or by adding letterboxing.
- Image editors like Photoshop and GIMP let you crop to a specific ratio or resize the canvas while keeping the image intact.
- Design tools like Figma and Canva let you change the artboard or document size to match your target ratio.
Changing aspect ratio in Adobe Premiere Pro
Open your project and go to File > Project Settings. In the General tab, you'll see the current video format. Click the dropdown next to "Video Display Format" and choose a preset ratio like 16:9, 4:3, or 1:1. If you need a custom ratio, select "Custom" and enter your own width and height values.
This changes the frame shape for all new sequences you create in this project. If you already have a sequence, right-click it in the Project panel and select Sequence Settings, then change the format the same way. Your existing clips will either letterbox (add black bars) or pillarbox (add side bars) to fit the new ratio without stretching.
If you want to crop your footage instead of adding bars, drag your clips into the frame and use the Scale effect to zoom in until they fill the new frame. This removes the bars but cuts off the edges of your original footage.
Changing aspect ratio in DaVinci Resolve
Create a new project and in the project settings, set your timeline resolution to your target ratio. Click the resolution dropdown and choose from presets like DCI 4K (17:9), UHD (16:9), or HD (16:9). You can also enter custom dimensions by typing the width and height directly.
If you're working in an existing project, go to File > Project Settings > Master Settings and change the timeline resolution there. Your clips will automatically fit to the new frame — if they don't fill it completely, use the Inspector panel on the right to scale or position them.
For precise control, click on a clip in the timeline and in the Inspector, adjust the Scale slider to zoom in or out, or use Pan to reposition it within the frame. This lets you decide what parts of the original footage stay visible.
Changing aspect ratio in Photoshop
If you want to crop your image to a specific ratio, select the Crop Tool from the toolbar (or press C). In the tool options at the top, click the dropdown that says "Aspect Ratio" and choose a preset like 16:9, 4:3, or 1:1. Then drag across your image to create a crop box in that ratio. Press Enter to apply.
If you want to change the canvas size instead of cropping, go to Image > Canvas Size. Enter your new width and height — the ratio will update automatically as you type. Choose where the existing image sits on the new canvas using the anchor grid, then click OK. This adds or removes space around your image without cutting anything off.
To resize the entire image to a new ratio, go to Image > Scale Image and change the width and height. Click the chain link icon between them to unlink the values if you want to stretch the image, or leave it linked to keep the original ratio and add space instead.
Changing aspect ratio in GIMP
Select the Rectangle Select Tool from the toolbar (or press R). In the tool options below the toolbar, check the box next to "Fixed" and choose "Aspect ratio" from the dropdown. Enter your desired ratio in the field next to it — for example, type 16:9 or 4:3.
Now drag across your image to create a selection in that exact ratio. Once you have the selection you want, go to Image > Crop to Selection to remove everything outside the box. This crops your image to the new ratio.
To change the canvas size instead, go to Image > Canvas Size and enter your new width and height. Use the offset grid to position your existing image on the new canvas, then click Resize. This adds space around your image without cropping it.
Changing aspect ratio in Figma
Click on your artboard (or frame) to select it. In the Design panel on the right, look for the width and height fields. Change these numbers to your target ratio — for example, 1920 × 1080 for 16:9, or 1080 × 1080 for 1:1. Your content will stay in place; the frame will resize around it.
If you want to use a preset ratio, click the dropdown arrow next to the dimension fields and select from common options like "Desktop", "Mobile", or "Instagram Post". Figma will automatically set the frame to that ratio. You can also create your own preset by entering custom dimensions and saving them.
Everything inside the frame will scale or reflow depending on how you've set up your constraints. If elements are pinned to specific edges, they'll stay in place. If they're set to fill, they'll resize with the frame.
Changing aspect ratio in Canva
Open your design and click the dropdown at the top that shows your current document size. Select "Custom dimensions" and enter your width and height. Canva will show you the ratio as you type. Click "Create" and your canvas will resize to the new ratio.
Alternatively, click the dropdown and choose from preset sizes like "Instagram Post" (1080 × 1080), "YouTube Thumbnail" (1280 × 720), or "Facebook Cover" (820 × 312). Your existing design will reflow to fit the new canvas — some elements may move or resize automatically.
If your design doesn't fit perfectly in the new ratio, you can manually move and resize elements by clicking and dragging them. Canva will show you guides to help you align things properly.
Frequently Asked Questions
What's the difference between cropping and letterboxing?
Cropping removes parts of your image or video to fit the new ratio — you lose content from the edges. Letterboxing adds black bars (or transparent space) to fill the frame without removing anything. Choose cropping if you want to keep the full frame size, or letterboxing if you want to preserve all the original content.
Will changing aspect ratio stretch or distort my image?
Not if you do it correctly. Most software lets you resize the canvas or frame without touching the image itself. The image stays its original shape; the space around it changes. Only if you manually stretch the width and height separately will you distort the content.
What aspect ratio should I use for social media?
Instagram posts are 1:1 (square), Instagram Stories are 9:16 (portrait), Facebook covers are roughly 16:9 (landscape), and YouTube thumbnails are 16:9. Check the platform's official specs before you start, because they change occasionally. Most design tools like Canva have these presets built in.
Can I change aspect ratio after I've finished editing?
Yes, but it's easier to set it at the start. If you change it after, you'll need to reposition or crop your content to fit the new frame. In video editors, this means adjusting scale and position for each clip. In image editors, you'll need to crop or add canvas space manually.
What if my software doesn't have a preset for my target ratio?
Use the custom dimensions option and enter your width and height directly. Calculate the ratio by dividing width by height — for example, 1920 ÷ 1080 = 1.78, which is 16:9. Most software will accept any custom dimensions you enter.