There is no single "best" format for every platform, but there is one safe default that plays everywhere: MP4 with H.264 video and AAC audio. From there, the only things that really change per platform are aspect ratio and resolution. This guide covers the settings that actually matter for TikTok, Instagram, and YouTube, and how to hit them in Supercut by typing a prompt, with nothing uploaded.
If you remember one thing, use MP4 with the H.264 video codec and AAC audio. Every major platform accepts it, every phone and browser plays it, and it keeps files small without obvious quality loss. TikTok, Instagram, and YouTube all re-encode whatever you give them, so handing over a clean H.264 MP4 gives their compression the best possible starting point. You do not need HEVC, VP9, or ProRes for a social post, and those formats often cause upload or playback errors. If your clip came off a phone, screen recorder, or download as MOV, WebM, or MKV, convert it to MP4 first.
Aspect ratio is what makes a clip feel native to a feed instead of letterboxed. For TikTok, Instagram Reels, and YouTube Shorts, export vertical 9:16 at 1080x1920 so it fills the phone screen. For a standard YouTube upload, use horizontal 16:9 at 1920x1080 (1080p), the sweet spot for sharpness versus file size. For a square Instagram feed post, 1:1 at 1080x1080 works well. Use 30fps as your default and reach for 60fps only when the source was actually shot at 60fps and the motion benefits, like sports or gameplay. Going above 1080p rarely helps for short clips, since the platforms compress hard on upload.
You do not need to obsess over bitrate. For 1080p, roughly 8 to 12 Mbps looks clean and stays well under platform upload caps. Keep audio as AAC at about 128 to 256 kbps. If a file is still too large to upload, compress it rather than dropping resolution first. Compression lowers the bitrate and shrinks the file while keeping the same dimensions, which almost always looks better than shrinking the frame to a smaller, softer image.
In Supercut you never dig through a codec menu. You type the result you want in plain English, like "export for TikTok" or "convert to MP4 and crop to 9:16 at 1080p." The AI plans the edit and a deterministic engine maps it to the right FFmpeg settings. Everything runs in your browser through WebAssembly, so your footage is never uploaded; only the text of your prompt is sent so the AI knows what to do. Built-in platform presets for TikTok, Reels, Shorts, Twitter, and Discord set the aspect ratio and encoding in a single step. Your first export is free to try with no account; unlimited watermark-free exports start at 4.99 per month billed yearly.
Open the Supercut editor and drag your video onto the page. It loads locally, with no upload and no account needed to try your first export.
Describe it plainly, like "export for TikTok" or "convert to MP4, crop to 9:16, 1080p." Supercut plans the format, aspect ratio, and resolution from your words.
The edit runs on your device and you get the result back in the page. Confirm the framing looks right vertical or horizontal before you save.
Download the finished MP4 to your device, then upload it to the platform. The whole process ran in your browser, so your original footage never left your machine.
Convert MOV, WebM, or other formats to MP4 in your browser. Universal playback without uploading your source file.
Crop and reframe any video to 9:16 for TikTok, Reels and Shorts. Subject-tracking keeps the action in frame, all in your browser, no upload.
Compress video to a smaller file size in your browser. Shrink clips for sharing without uploading them anywhere, your footage stays on your device.
Reframe, caption, and batch-process client clips in your browser. No uploading client footage to a third party, and no watermark on paid exports.
Reframe to 9:16, add viral captions, trim hooks, and export TikTok-ready clips in your browser. No upload before you post.
MP4 with the H.264 video codec and AAC audio. TikTok, Instagram, and YouTube all accept it, it plays on every device, and it gives the platforms a clean file to re-encode. Use it as your default and change only the aspect ratio and resolution per platform.
Vertical 9:16 at 1080x1920 is the standard for TikTok, Instagram Reels, and YouTube Shorts. It fills the phone screen with no black bars. Going higher than 1080p rarely helps, because the platforms compress after upload.
No. Supercut runs entirely in your browser using WebAssembly (FFmpeg.wasm), so your footage never leaves your device. Only the text of your prompt is sent so the AI knows what edit to plan.
Compress it. Compression lowers the bitrate and shrinks the file while keeping the same dimensions, which usually looks better than reducing the resolution. In Supercut you can just say "compress this for upload."
Only if your source was actually recorded at 60fps and the motion benefits, like fast action or gaming. For most social clips, 30fps is a fine default and keeps file sizes lower.