Video aspect ratios: which format to choose for your platform
Your video format determines how your clip looks on the viewer's screen. We break down 16:9, 9:16, 1:1 and 4:5, give you a table for every platform, and show how to lock in your format right at the start of your project in Reelora.
What aspect ratio is and why you need it
Aspect ratio is the proportion of frame width to height. The notation 16:9 means that for every 16 units of width there are 9 units of height. It's exactly this proportion that defines the frame your video will "fit" into on the viewer's screen.
Choose your video format before you start working, not after. Frame composition, object placement, text and subtitle size — everything is built around specific proportions. Horizontal video squeezed onto a vertical screen looks like a foreign fragment with black bars — and viewers just scroll past.
In Reelora, the format is set when you create a project: you pick whether you're making a long video or a short, and then the whole framework — prompts, references, voiceover, editing — is built around that format.
- 16:9 — horizontal frame for YouTube long-form videos and the web
- 9:16 — vertical frame for Shorts, TikTok and Reels
- 1:1 — square for Facebook and Instagram feeds
- 4:5 — vertical post that takes up more space in the feed
Format table for major platforms
| Aspect ratio | Typical resolution | Where it's used | When to choose it |
|---|---|---|---|
| 16:9 | 1920×1080 | YouTube (regular videos), Facebook, websites, presentations | Long-form content, tutorials, web promos |
| 9:16 | 1080×1920 | YouTube Shorts, TikTok, Instagram Reels, Stories | Shorts and mobile-first vertical content |
| 1:1 | 1080×1080 | Instagram and Facebook feed | Compact video posts without a strong orientation |
| 4:5 | 1080×1350 | Instagram and Facebook feed | Vertical posts that take up maximum space in the feed |
16:9 and 9:16: the two main formats of modern content
16:9 is the classic. It's how TV, YouTube long-form videos, webinars and presentations are shot. If your clip runs longer than a minute and will be watched on a computer or TV, this is almost always the format you need. It comfortably fits two people, diagrams, screenshots and captions in one frame.
9:16 is the phone format. Shorts, TikTok and Reels live here: the video fills the whole screen, no bars, no distractions. For shorts it's not "one of the options" but a basic platform requirement. We've covered this exact scenario in detail in our shorts guide.
The practical rule is simple: long YouTube video — 16:9, short vertical video for mobile feeds — 9:16. Everything else derives from these two.
1:1 and 4:5: formats for social media feeds
The 1:1 square is a neutral option for posts in the Instagram and Facebook feed. It looks the same on phone and desktop and asks nothing extra from the viewer. The downside: it takes up less screen space than its vertical rivals.
4:5 is a compromise between the square and full-screen vertical. In the feed, such a video takes up noticeably more area, so it grabs attention better while scrolling. It's a popular choice for ads and promo posts.
Both formats are about fitting naturally inside the feed. If your goal is Reels or Stories, go full 9:16.
How to pick a format at the start of a project in Reelora
Define the platform and the goal
One sentence: where the video will live and what the viewer should do. "A short for a travel channel" is already enough to know: you need 9:16.
Choose the mode: long or short
When creating a video in Reelora, you set the approximate length, format, topic and language. This choice immediately locks in the proportions of your future frames.
Check the framework
The AI assembles the framework of your future video: prompts for voiceover, photos and clips are already in place and match the chosen format. If you haven't been through this flow yet, check out our guide to making AI videos.
Generate the first frame and evaluate the composition
See how the scene fits the proportions. If something feels cramped or empty — fix the prompt now instead of waiting for the final cut.
Replace weak frames individually
Any single frame can be regenerated or swapped for your own footage without redoing the whole video.
Finalize and check on a phone
After editing with voiceover and subtitles, watch the final version on the device your audience will use.
Frequently asked questions about video formats
Can I change the format after the project has been created?
Individual frames can be regenerated for different proportions, but that's essentially new composition work. Choosing the format at the start saves far more time — then the entire framework, prompts and editing are built around it from the get-go.
Which format should I choose for YouTube?
For regular long videos — 16:9. For Shorts — strictly 9:16. These are different delivery mechanics, so plan them as separate videos rather than a cropped copy of one.
Can I make one story in several formats at once?
Yes, and it's common practice: a horizontal version for YouTube plus a vertical cut for Shorts and Reels. Batch generation in Reelora lets you launch several variants at once and collect the ready results in your project.
Does the format affect generation quality?
The model builds the frame composition around the given proportions: in 9:16 it keeps the main subject vertical, in 16:9 it spreads the scene across the width. Problems only appear if you try to squeeze a finished frame into different proportions.
Which is better for Instagram — 1:1 or 4:5?
For feed posts, 4:5 usually works better: it takes up more screen space. Go with the 1:1 square when you need a neutral, symmetrical frame. For Reels and Stories — 9:16 only.
Do subtitles adapt to the format?
Yes. Automatic subtitles in Reelora recognize speech, split it into lines and burn them into the video taking the frame proportions into account — in vertical format the text is placed so it doesn't cover anything important.
How much does generation cost in different formats?
Reelora runs on a pay-as-you-go model: you pay only for what's actually generated. Always check current prices on the website — they may change.
See also
Pick your format — and start generating
Open Reelora, set your format and topic — the studio will assemble the framework of your future video while you control every frame. You pay only for what's actually generated.
Create a video in Reelora