Video & Audio File Size / Bitrate Calculator
Estimate a video or audio file's size from bitrate and duration — or find the bitrate you need to hit a target size (e.g. under 25 MB for Discord or email).
How to use
- 1Enter the duration and video + audio bitrates to get the file size.
- 2Or switch to 'Bitrate for a target size' and enter the size limit.
How it's calculated
Size (MB) = (video kbps + audio kbps) × seconds ÷ 8 ÷ 1000. Bitrate for a target = size × 8 × 1000 ÷ seconds − audio kbps. Containers add about 1–2% overhead.
Frequently asked questions
What bitrate should I use for 1080p?
About 8 Mbps for 30 fps and 12 Mbps for 60 fps (YouTube's SDR upload recommendations). Streaming at 1080p typically uses 4.5–6 Mbps.
Why is my file slightly bigger than calculated?
Containers (MP4, MKV) and variable bitrate encoding add a small overhead. Aim 2–5% under a hard limit.
How do I make a video under 25 MB?
Use 'Bitrate for a target size', enter 24 MB to leave headroom, and encode at the resulting video bitrate with a two-pass encode.