Change the aspect ratio before you start editing

The fastest way to set aspect ratio in DaVinci Resolve is to choose it when you create a new project, before you import any footage. Open DaVinci Resolve, click File > New Project, name your project, then click Create. In the project settings window that opens, go to the Master Settings tab. Under Timeline Resolution, you will see a dropdown that says Resolution — this is where you pick your aspect ratio.

Common aspect ratios are listed by name: 1920x1080 (16:9, standard HD), 3840x2160 (16:9, 4K), 1280x720 (16:9, 720p), and 4096x2160 (DCI 4K, used in cinema). If you need a square format (1:1) for social media, select 1080x1080. For vertical video (9:16), you can use 1080x1920. Once you pick a resolution, click Save and you are ready to import footage.

Key Takeaways

  • Set aspect ratio in Master Settings under Timeline Resolution when you create a new project, before importing footage.
  • You can change aspect ratio after editing by creating a new timeline with different resolution settings and copying your edit into it, though this requires extra steps.
  • The aspect ratio you choose affects the canvas size and how your footage displays, not the original file itself.
  • Common formats are 16:9 (1920x1080 for HD, 3840x2160 for 4K), 1:1 (1080x1080 for social media), and 9:16 (1080x1920 for vertical video).

Change aspect ratio after you have already started editing

If you have already built a timeline and need to change the aspect ratio, you cannot straightforward click a button to resize it. Instead, you must create a new timeline with the correct resolution and move your edit into it. Go to File > New Timeline. In the dialog, name the new timeline and choose the resolution you want from the dropdown. Click Create.

Now you have two timelines open in the same project. Click on your original timeline to select it, then press Ctrl+A (Windows) or Cmd+A (Mac) to select all clips. Press Ctrl+C or Cmd+C to copy. Switch to the new timeline by clicking its tab at the bottom of the screen, click at the start of the timeline, and press Ctrl+V or Cmd+V to paste. Your entire edit now sits in the new aspect ratio.

Be aware that changing aspect ratio after editing can cause problems if your original footage does not match the new dimensions. Footage shot in 16:9 will look stretched or letterboxed if you force it into a 1:1 square timeline. Test how your clips look before you commit to the new format.

Understand the difference between project resolution and output resolution

Your project resolution (the aspect ratio you set in Master Settings) controls the canvas size while you edit. Your output resolution is what you export as — the final file format. These do not have to match. You can edit in 1920x1080 and export as 3840x2160, or vice versa, though exporting to a larger size than your source footage will look soft.

When you export, go to File > Export and choose your codec. In the export settings, you will see Resolution options. You can pick a different resolution here than your timeline uses. If you want to create multiple versions of the same edit — one for YouTube (16:9), one for Instagram (1:1), and one for TikTok (9:16) — edit once in your preferred timeline, then export three times with different output resolutions.

Use the Fusion page to reframe footage for a different aspect ratio

If you have footage shot in one aspect ratio but need it to fit another without black bars, you can use the Fusion page to zoom and reposition the image. This is useful when you have 16:9 footage but need to fill a 1:1 square timeline. Go to the Fusion page, select the clip, and in the Inspector panel on the right, find the Transform section. Adjust the Scale slider to zoom the image until it fills the frame, then use Offset X and Offset Y to reposition it so the important part of the image stays visible.

This method works but crops part of the original image. You lose picture information on the sides or top and bottom. Use it only when you have room to reframe — a wide shot of a landscape might work, but a close-up of a face may not have enough extra pixels to reframe without cutting off important details.

Add letterboxing or pillarboxing if you want to keep the whole image

Letterboxing is the black bars you see on top and bottom when a wide image plays on a narrow screen. Pillarboxing is the black bars on the sides. If you want to change aspect ratio without cropping any of the original image, you can add these bars in DaVinci Resolve. Go to the Edit page, right-click the clip in the timeline, and select Clip Attributes. Under Sizing, choose Fit to Fill or Center depending on how you want the image positioned. The software will add black bars to fill the empty space.

This preserves the entire original image but means part of your timeline will be black. It is the safest choice if you are unsure whether cropping will lose important content, and it is standard practice for cinema and broadcast television.

Check your footage resolution before you choose a project aspect ratio

Before you create a new project, know what resolution your camera or source footage is recorded in. If your camera shoots 1920x1080, setting your project to 4K (3840x2160) will force DaVinci Resolve to upscale the footage, which makes it look soft and blurry. If your camera shoots 4K but you set your project to 1080p, the software will downscale, which wastes the detail in your original files.

Check your footage by opening it in your file browser or by importing one clip into a temporary timeline and looking at its properties. Match your project resolution to your source footage as closely as possible. If you have mixed footage — some 1080p and some 4K — set your project to the highest resolution and let DaVinci Resolve scale the lower-resolution clips up. The 1080p footage will not look worse than it already is, and the 4K footage will stay sharp.

Frequently Asked Questions

Can I change aspect ratio without losing my edit?

Yes. Create a new timeline with the aspect ratio you want, copy all your clips from the old timeline, and paste them into the new one. Your edits, transitions, and color grading stay intact. The only thing that changes is the canvas size around your footage.

What aspect ratio should I use for social media?

Use 16:9 (1920x1080) for YouTube and most websites. Use 1:1 (1080x1080) for Instagram feed posts and Facebook. Use 9:16 (1080x1920) for TikTok, Instagram Reels, and YouTube Shorts. If you are unsure, edit in 16:9 and export three separate versions with different output resolutions.

Why does my footage look stretched or squished after I changed aspect ratio?

This happens when you change the aspect ratio without adjusting how the footage fits. Right-click the clip, go to Clip Attributes, and under Sizing choose Fit to Fill or Center. This will either zoom the image to fill the frame or add black bars, depending on which option you pick.

Is it better to change aspect ratio before or after editing?

Change it before you start. Setting the aspect ratio first means you see exactly how your footage will look in the final format while you edit. Changing it after means extra work and a higher chance of mistakes. If you must change it after, create a new timeline and copy your edit into it.

Can I export in a different aspect ratio than my project uses?

Yes. Your project resolution and export resolution are separate. You can edit in 1920x1080 and export as 3840x2160, or edit in 4K and export as 1080p. Keep in mind that exporting to a larger size than your source footage will not add detail — it will just make the image look softer.