Instagram Reels and TikTok both re-encode every video you upload. That means whatever you provide gets converted to their internal format — you have no control over the final output quality on the platform. What you do control is the quality of the source you give them. A better source produces a better result after their re-encode. Giving them a poorly compressed or wrong-format video introduces additional quality loss.
What Instagram Reels expects
Instagram's recommended video specs for Reels are:
- Container: MP4
- Video codec: H.264
- Audio codec: AAC
- Frame rate: 23–60 fps
- Aspect ratio: 9:16 (vertical), 1:1 (square), or 16:9 (horizontal)
- Recommended resolution: 1080 x 1920 for vertical Reels
- Bitrate: Instagram accepts up to around 3.5 Mbps, though they will re-encode regardless
The most important thing is to upload an MP4 with H.264 video and AAC audio. If you give Instagram a MOV file (common on iPhone), it works but goes through an additional conversion step. WEBM files are not reliably handled. MKV is generally not accepted. Stick to MP4.
For vertical Reels (9:16), aim for 1080 x 1920. Horizontal content works but performs worse in the algorithm on mobile — most viewers see Reels in full-screen vertical format. If you have landscape footage, consider cropping to vertical before uploading.
What TikTok expects
TikTok's recommended specs are similar:
- Container: MP4 or MOV
- Video codec: H.264 or H.265
- Resolution: 1080 x 1920 for vertical, up to 4K for horizontal
- Frame rate: 23–60 fps
- Audio: stereo AAC at 44.1 kHz
TikTok handles H.265 (HEVC) better than Instagram does, which is worth knowing if you record with an iPhone using High Efficiency mode. MP4 with H.264 is still the safest universal choice.
Why format matters even when they re-encode
Every time a video is encoded, some quality is lost. If you start with a heavily compressed source — for example, a video that has already been downloaded from another platform and re-shared — you are starting with a file that has already lost quality once. Instagram or TikTok then compress it again. You can see this in action when you save a video from either platform and try to re-upload it: it looks noticeably softer than the original upload.
The practical lesson: always upload from the best-quality version of your source file. If you recorded on your phone, export from the camera roll, not from a preview in another app. If you edited in a video editor, export at high quality (low CRF, high bitrate) and then let the platform do its own compression.
Converting your video to the right format
If your source file is in MOV, WEBM, AVI, MKV, or any format other than MP4 H.264, you can convert it in your browser using the ClipZap format converter. Upload your file, select MP4 as the output, and download the converted file. No software installation required, and your file never leaves your device.
For resizing to 1080 x 1920 vertical format, use the ClipZap resize tool. Set width to 1080 and height to 1920, or choose the appropriate preset if available. This is useful when you have horizontal (landscape) source footage that you want to adapt for Reels or TikTok.
Summary: what to do
Export or convert your video to MP4 with H.264 video and AAC audio. For vertical content, target 1080 x 1920. Keep the source quality high — do not over-compress before uploading. The platform will compress it regardless; your job is to give them the best possible starting point.