Correction, 2026-10-02: this page said Meta recommends 4:5 for Instagram feed video ads. Meta's English guide now recommends 9:16 (1080 x 1920) for Instagram feed video; 4:5 is its recommendation for Facebook feed video and Instagram feed images.
Correction, 2026-10-01: this page said Kling v3 is 8frame's default model for vertical social content, generates 9:16 natively and takes roughly 45 to 60 seconds for a 5-second clip. On 8frame, Kling v3 Standard and Pro need a start image and take that image's shape, nothing makes Kling v3 the default for vertical work, and we have no measured generation time. The page also suggested Veo 3.1 for square video and a 2.39:1 Veo output through a "custom crop target" in the canvas: Veo 3.1 makes 16:9 and 9:16 only, no video model on 8frame generates 2.39:1, and we could not confirm any such crop setting. It called a vertical clip in a wide player "letterboxed" (bars at the sides are pillarboxing), introduced four ratios as three, and stated quality claims we have not measured. The examples now use the shapes each model offers, the platform claims carry sources, and the page has a FAQ.
Correction, 2026-09-30: We said Veo 3.1 targets 4K and Kling v3 1080p; on 8frame they are 1080p and 720p. We also said a 4K Veo 3.1 clip renders in about 90 seconds; it renders at 1080p on 8frame, and we have no measured timing for it.
Aspect ratio is the proportional relationship between a frame's width and height, expressed as two numbers separated by a colon, such as 16:9 or 9:16.
It's one of the first decisions you make in any video or image workflow because it decides where the content can go. TikTok recommends 9:16 for in-feed ad video, and Meta specifies 9:16 for Instagram Reels ads. On a computer, YouTube's standard player is 16:9, and YouTube may add padding around a 9:16 vertical video there. Aspect ratio is a distribution decision as much as a creative one.
How aspect ratio works
The two numbers in a ratio describe width relative to height. A 16:9 frame is 16 units wide for every 9 units tall. A 9:16 frame flips that, taller than it is wide. The actual pixel dimensions can vary (1920x1080 and 1280x720 are both 16:9) as long as the ratio holds.
In AI generation, aspect ratio is usually a setting you choose before generating, not a crop you apply afterwards: the clip comes out in that shape. So write the prompt for the frame you will deliver: where the subject sits, what fills the top and bottom of a vertical frame, which way the motion runs. One exception matters on 8frame: with a start image, Kling v3, Wan 3.0 and Hailuo H3 follow the image's shape instead of a ratio setting, so make the image in the final shape.
The ratios that come up most often:
- 9:16 (vertical). Taller than wide. TikTok recommends it for in-feed ads, Meta specifies it for Instagram Reels ads, and YouTube counts square and vertical uploads up to three minutes long as Shorts.
- 1:1 (square). Equal sides. TikTok's in-feed ads accept it alongside 9:16 and 16:9.
- 4:5 (portrait). Slightly taller than square. Meta recommends it for Facebook feed video ads and Instagram feed image ads; its English guide for Instagram feed video now recommends 9:16.
- 16:9 (horizontal widescreen). The standard aspect ratio for YouTube on a computer, and the shape YouTube suggests for long-form videos that should not be classified as Shorts.
- 2.39:1 (anamorphic widescreen). An ultra-wide cinematic format used in film and in brand films that want that look.
When you use each ratio
Deliver in the shape the placement expects, not the one that's easiest to produce.
9:16 is the shape for social-first campaigns on TikTok, Reels and Shorts. A 16:9 clip in a vertical slot is either cropped at the sides or shown small with bars above and below (letterboxed).
1:1 works where the frame has to hold its own in a grid or a square slot, such as product listings and the ad placements that accept it.
4:5 is for Facebook feed video ads and Instagram feed image ads. No video model on 8frame generates it, so generate 3:4 or 9:16 and crop.
16:9 is the right call for YouTube long-form, embedded web video, and any context where the viewer is on a laptop or desktop.
2.39:1 is a specialty ratio for brand films and cinematic content where you want the wide-screen look associated with theatrical releases. You're trading feed compatibility for the look, and you get it by cropping: cropping a 16:9 frame to 2.39:1 keeps about 74% of its height, and cropping 21:9 keeps about 98%.
Which 8frame video models make each ratio
| Ratio | Video models on 8frame that generate it |
|---|---|
| 16:9 and 9:16 | Every video model; for Kling v3, start from an image in that shape |
| 1:1 | Kling 2.6 Pro and Wan 3.0 (from text), Seedance, Hailuo H3, Grok Imagine, Happy Horse, Pruna p-video, Creatify Boreal, Runway Gen-4 Turbo. Not Veo 3.1 or Gemini Omni Flash |
| 4:3 and 3:4 | Seedance, Hailuo H3, Grok Imagine, Happy Horse, Pruna p-video, Creatify Boreal, Runway Gen-4 Turbo |
| 21:9 | Hailuo H3 (from text), Runway Gen-4 Turbo |
| 4:5 and 2.39:1 | None: generate a nearby shape and crop |
| The start image's shape | Kling v3 (which needs a start image), and Wan 3.0 and Hailuo H3 when you start from an image; Seedance's "Auto" option |
The full list, model by model, is in AI video aspect ratios by model.
Examples
9:16, TikTok and Reels: from text, set 9:16 on a model that offers it: Kling 2.6 Pro (95 credits for 5 seconds with sound, 47 silent), Wan 3.0 (24, 48 or 95 credits for 5 seconds at 480p, 720p or 1080p), Seedance, Hailuo H3 or Veo 3.1. Kling v3, the model the Kling tool opens on, needs a start image and takes its shape, so start it from a vertical image: a Seedream 5 Lite frame (6 credits) plus a 5-second Kling v3 Standard clip with sound (86) comes to 92 credits.
1:1, product listings and square slots: Veo 3.1 does not make square video. Kling 2.6 Pro and Wan 3.0 offer 1:1 from text, and so do Seedance, Hailuo H3 and Grok Imagine. For stills, every image model on 8frame offers 1:1; the shapes per image model are in AI image aspect ratios by model. Generating square keeps the whole frame, while cropping a 16:9 clip to square keeps only 56% of its width.
16:9, YouTube and landing pages: every video model on 8frame offers 16:9. Veo 3.1 renders 16:9 or 9:16 at 1080p (Lite at 720p), in 4, 6 or 8 seconds from text; the Veo tool opens on Veo 3.1 Fast, 168 credits for 8 seconds with sound. Wan 3.0 at 1080p is 95 credits for 5 seconds.
2.39:1, cinematic brand film: generate 21:9 on Hailuo H3 from text (88 credits for 5 seconds at 2K) and trim the small difference, or generate 16:9 and crop the top and bottom in your editor. Keep the action in the middle band of the frame so the crop doesn't cut it.
Related concepts
- For how to choose models and ratios for an ecommerce ad campaign, see AI video for ecommerce: the complete 2026 guide.
- To see aspect ratio inside a UGC workflow (9:16, lifestyle prompt), see how to make a UGC ad with AI.
- Resolution and aspect ratio are related but separate. Two clips can share a 16:9 ratio at very different pixel counts: Wan 3.0 offers 480p, 720p and 1080p in the same shapes, and Veo 3.1 renders at 1080p (Lite at 720p).
FAQ
What is aspect ratio in simple terms?
Width compared with height, written as two numbers: 16:9 is wide, 9:16 is tall, 1:1 is square.
What aspect ratio should I use for TikTok and Reels?
9:16. TikTok recommends it for in-feed ads, and Meta specifies it for Instagram Reels ads.
Can Veo 3.1 make square video?
No. On 8frame, Veo 3.1 makes 16:9 and 9:16 only. For 1:1, use Kling 2.6 Pro or Wan 3.0 from text, or Seedance, Hailuo H3 or Grok Imagine.
Why did my clip come out in a different shape from the one I set?
With a start image, Kling v3, Wan 3.0 and Hailuo H3 follow the image's shape instead of the ratio setting. Make the start image in the shape you need.
Can AI video models on 8frame generate 4:5 or 2.39:1?
No. For 4:5, generate 3:4 or 9:16 and crop. For 2.39:1, generate 21:9 or 16:9 and crop.
Sources
- TikTok Ads Manager help, "TikTok Auction In-Feed Ads": vertical 9:16 (recommended), horizontal 16:9 and square 1:1: ads.tiktok.com/help/article/tiktok-auction-in-feed-ads, checked 2026-10-01
- Meta Ads Guide, Instagram Reels video: 9:16: facebook.com/business/ads-guide/update/video/instagram-reels, checked 2026-10-01
- Meta Ads Guide, English versions: Facebook feed video 4:5, 1440 x 1800 (facebook.com/business/ads-guide/update/video/facebook-feed); Instagram feed video 9:16, 1080 x 1920 (facebook.com/business/ads-guide/update/video/instagram-feed), both checked 2026-10-02
- YouTube Help, "Video resolution & aspect ratios": "The standard aspect ratio for YouTube on a computer is 16:9", and padding for 9:16 vertical videos on computer browsers: support.google.com/youtube/answer/6375112, checked 2026-10-01
- YouTube Help, "Understand three-minute YouTube Shorts": square or vertical uploads up to three minutes are categorized as Shorts; "use a wider aspect ratio such as 16:9 for long-form videos": support.google.com/youtube/answer/15424877, checked 2026-10-01
- Aspect ratios per model, which models follow the start image, the Kling v3 start-image requirement and the Kling and Veo tool defaults: 8frame aspect-ratio configuration, tool registry and video generation code, read 2026-10-01
- Prices: 8frame tool registry credit functions (calculateKling26Cost, calculateKlingV3Cost, calculateVeo31Cost, Wan 3.0 and Hailuo H3 rates, Seedream 5 Lite), read 2026-10-01
Ready to generate platform-native video at the right aspect ratio? AI video for ecommerce: the complete 2026 guide covers model selection, prompt structure and output specs for ecommerce video.
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