Free tool · Video files
Video file size and bitrate calculator
File size = (video bitrate + audio bitrate) × duration ÷ 8. Enter a bitrate and a duration to get the size, or switch modes and enter a target size to get the bitrate that fits it.
Inputs
File size
385 MB
366.8 MiB
Per minute
38.5 MB
Total bitrate
5.128 Mbps
How the video file size and bitrate calculator works
Bitrate is bits per second. Multiply by the duration in seconds to get bits, divide by 8 for bytes. A 10-minute video at 5 Mbps video plus 128 kbps audio is (5 + 0.128) × 600 ÷ 8 = 384.6 MB.
In target-size mode the calculator reverses the formula: it converts the size to bits, divides by the duration, and subtracts the audio bitrate to give the video bitrate to set in your encoder.
Containers (MP4, MKV, MOV) add about 1–2% for indexes and metadata, so leave a small margin when you must stay under an upload limit.
Frequently asked questions
Why is my exported file a different size?
Encoders using variable bitrate (VBR or CRF) spend more bits on complex scenes and fewer on simple ones, so the real average can differ from the target. Two-pass encoding hits a target size most closely.
Is the result in MB or MiB?
Both are shown. MB is decimal (1,000,000 bytes), which storage makers and most upload limits use. MiB is binary (1,048,576 bytes), which some operating systems show.
What bitrate should I use for 1080p?
For web delivery, 1080p at 30 fps usually looks good at 5–8 Mbps in H.264. Fast motion or 60 fps needs more; H.265 and AV1 need less for the same quality.
Does audio change the file size much?
Usually only a little. 128 kbps stereo AAC adds about 0.96 MB per minute, while a 5 Mbps video stream adds about 37.5 MB per minute.