Guides to video sizes, compression and formats
Short explanations of how video and audio files work, written to help you get a better result from the converters and from the apps you post to.
- Video sizes for Reels, Shorts and TikTokThe one export setting that works for all three apps, and the length limits that differ.
- Bitrate, resolution and file size: how they fit togetherThe sums behind video file size, and how to work back from a size limit.
- How to get a video under 16 MB for WhatsAppCompress it yourself or send it as a document, and what 16 MB allows at each length.
- Why videos look blurry after uploadWhat apps do to your upload, what you can control, and what you cannot.
- GIF or MP4: which should you use?Why GIFs are so large, when one is still the right choice, and how to keep it small.
- Instagram captions: line breaks, length and the 5 hashtag limitCaption length, keeping your line breaks, and choosing five hashtags.
- How to trim a video without losing qualityHow a keyframe cut keeps the original quality, and its one limitation.
- Extract audio from a video: M4A, MP3 or WAV?How to save a video's sound with no quality loss, and which format to pick.
Where to start
- A video is too big to send. Read How to get a video under 16 MB for WhatsApp, then use the video compressor.
- A video looks worse after posting. Read Why videos look blurry after upload and check the file with the reel size checker.
- You are not sure what bitrate or resolution to pick. Bitrate, resolution and file size: how they fit together explains how the three relate, with worked sizes.
- You only need the sound. Extract audio from a video: M4A, MP3 or WAV? covers which format to save it in.
What the guides cover, and what they do not
Each guide explains one thing a converter does and why it behaves as it does: why a file is the size it is, why a cut lands where it lands, why an app changes your video after you post it. They are written for someone holding a phone and a file, not for video engineers, so they give the working rule first and the reasoning after.
They do not cover editing, filters, music or growing an audience, and they do not explain how to take videos from other people's accounts.
How the figures are kept accurate
Apps change their limits often and do not always announce it. Every limit quoted in a guide carries the month it was last checked, which is currently October 2026, and says so when a figure comes from third-party reports and not from the app's own help pages. If you find one that is out of date, please tell us.