Video file size and bitrate calculator

Choose Bitrate, enter the size limit and the length, and the calculator runs the formula backwards: it keeps some headroom spare (5% by default), takes off the container, and divides what is left by the duration. Then it subtracts the audio, and what remains is the average video bitrate to give your encoder.

The headroom is there because an encoder set to an average bitrate does not hit it exactly. Two-pass encoding usually lands close; a single pass can drift further. If a platform rejects files over a hard limit, keep the headroom. If the audio alone needs more than the limit allows, the calculator says so rather than showing a negative bitrate.

Choose Bitrate, enter 3:00 and 25 MB, keep 128 kbps audio, 1% overhead and 5% headroom. The usable size is 23.75 MB, or about 23.5 MB of streams after the container — 1,045 kbps in total over 180 seconds. Taking off the audio leaves about 917 kbps (0.92 Mbps) of video.

Open Assumptions and picture size and pick 1080p at 30 fps. That is about 0.015 bits per pixel, low enough that small text will soften whenever the screen scrolls. The same bitrate at 720p gives each pixel more than twice as much data. For a recording that has to stay small, a smaller picture often reads better than a starved large one.

These are YouTube’s recommended upload bitrates for standard video, with 128 kbps audio and 1% overhead. They are recommendations for an upload that will be re-encoded, not minimums: a screen recording that mostly holds still often looks fine at far less.

Not on its own. Bitrate is how much data the encoder may spend; whether a menu label is readable also depends on the size it was captured at, how much of the screen moves at once, and how the player scales it. A label too small to read in the original stays too small at any bitrate. The bits-per-pixel figure is only a way to compare settings with each other.

For a screen recording, the order that usually helps: capture the window at the size viewers will see it, zoom in on the part that matters, keep scrolling slow, and only then raise the bitrate. How to make a tutorial video covers planning, recording and exporting a lesson end to end. When a finished file is over its limit, the video compressor re-encodes it to fit.

Read figures from a video file fills in the length, the audio bitrate, the picture size and the frame rate from a video you already have. The overall bitrate is the file’s size divided by its length; the video figure is what is left after the audio and the container overhead you set, so the calculator gives back the file’s own size. The file is opened in your browser with Mediabunny, which is downloaded only when you pick a file; nothing is uploaded and the file is not decoded. A WebM straight from a browser recorder may not record its length, and then cannot be read.

• It is an estimate of an encoded file, not a guarantee. Encoders vary from the bitrate you set, and quality-based modes such as CRF vary with what is on screen.
• Container overhead is a percentage you choose. Very short clips and files with many tracks, chapters or subtitles carry proportionally more.
• Variable-bitrate audio, multiple audio tracks and embedded thumbnails are not modelled separately; add them to the audio figure if you need to.
• Platform limits change. Check the current limit where you are sending the file.