Free bitrate calculator for video and audio. Get file size from bitrate and duration, find the bitrate for a target size, or estimate recording length.
YouTube figures are for SDR uploads. Twitch publishes one figure per resolution and frame rate, and recommends constant bitrate.
| Target | 24-30 fps | 48-60 fps |
|---|---|---|
| YouTube 2160p (4K) | 35,000 kbps | 53,000 kbps |
| YouTube 1440p (2K) | 16,000 kbps | 24,000 kbps |
| YouTube 1080p | 8,000 kbps | 12,000 kbps |
| YouTube 720p | 5,000 kbps | 7,500 kbps |
| YouTube 480p | 2,500 kbps | 4,000 kbps |
| Twitch 1080p | 4,500 kbps | 6,000 kbps |
| Twitch 720p | 3,000 kbps | 4,500 kbps |
Upload recommendations from YouTube, and ingest guidance from Twitch.
| Track | Bitrate |
|---|---|
| Twitch ingest (AAC) | 96 kbps |
| Twitch maximum (AAC) | 160 kbps |
| YouTube mono | 128 kbps |
| YouTube stereo | 384 kbps |
| YouTube 5.1 | 512 kbps |
Capacities in decimal gigabytes, as the standards state them.
| Medium | Capacity | Source |
|---|---|---|
| DVD-5 (single layer) | 4.7 GB | ECMA-267 |
| DVD-9 (dual layer) | 8.5 GB | ECMA-267 |
| Blu-ray BD-25 | 25 GB | Nominal |
| Blu-ray BD-50 | 50 GB | Nominal |
Results are theoretical values from the bitrate, duration and audio track you enter. Real files vary with container overhead, variable-bitrate encoding and codec efficiency.
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Whether you are uploading to YouTube, streaming to Twitch, authoring a disc or sizing a security-camera archive, bitrate is the one number that decides both quality and storage. This calculator solves any of the three linked quantities - bitrate, file size, duration - from the other two, adds the audio track that most calculators ignore, and tells you which optical media the result still fits on.
Bitrate is how much data a video or audio file spends on each second of playback, quoted in kilobits or megabits per second. Higher bitrate means more detail survives compression, and a proportionally larger file. Because a byte is eight bits, converting between a rate and a size is a division by eight - the arithmetic is exact, and only the unit convention causes confusion. A real media file also carries an audio track, so the size that lands on disk reflects the video bitrate plus the audio bitrate, not the video figure alone.
Bitrate Formula
YouTube recommends 8 Mbps for 1080p SDR at 24-30 fps. A 10-minute upload at that rate is 600 MB of video, plus about 29 MB for a 384 kbps stereo track.
Twitch publishes 4,500 kbps for 720p60 and 6,000 kbps for 1080p60, both CBR. A 3-hour stream recorded locally at 720p60 is roughly 6.1 GB.
A single 2 Mbps camera recording continuously produces about 21.6 GB a day, so a 30-day retention window needs roughly 648 GB per camera before redundancy.
A 90-minute feature onto a 4.7 GB DVD-5 leaves about 7 Mbps for video and audio combined; the same feature onto a 25 GB Blu-ray allows roughly 37 Mbps.
Know before you record how much space a shoot, a stream archive or a 24/7 camera feed will consume, so you buy the right card or drive once.
Match your encoder to what the platform actually recommends and to the upload bandwidth you really have, rather than pushing a bitrate your connection cannot sustain.
Work backwards from a hard limit - a 4.7 GB DVD, a 25 GB Blu-ray, an upload cap - to the highest bitrate that still fits, instead of encoding twice.
See the exact byte count alongside the rounded figure, and switch between decimal MB and binary MiB, so the number you quote is the number you mean.
YouTube's published recommendations for SDR uploads are 8 Mbps at 1080p and 12 Mbps at high frame rate, 5 and 7.5 Mbps at 720p, and 35-45 Mbps at 4K rising to 53-68 Mbps at 50 or 60 fps. Twitch is lower because it is live: 4,500 kbps at 720p60 and 6,000 kbps at 1080p60.
Both conventions exist, which is why this calculator makes it an explicit choice. Bitrates are always decimal - 1 Mbps is exactly 1,000,000 bits per second. For file size, NIST reserves the kilo, mega and giga prefixes for powers of 1,000 and names the powers of 1,024 kibi, mebi and gibi. Choose decimal and you see MB; choose binary and you see MiB, never a decimal label over a binary figure.
Three reasons. A container such as MP4 or MKV adds indexes and headers, typically well under two percent. Variable bitrate encoding spends fewer bits on simple scenes, so the average lands under the target. And an encoder treats your target as a ceiling rather than a quota. Expect the real file to come in at or slightly below the calculated size.
Constant bitrate holds the rate steady, which makes the file size predictable and the stream stable - Twitch recommends CBR for exactly that reason, because a variable stream drops its rate during quiet moments and can trigger buffering. Variable bitrate spends bits where the picture needs them, giving better quality per megabyte but a size you can only estimate.
It matters more at low video bitrates than high ones. YouTube recommends 128 kbps for mono, 384 kbps for stereo and 512 kbps for 5.1; Twitch suggests 96 kbps for ingest and caps AAC at 160 kbps. Against an 8 Mbps 1080p video a 384 kbps stereo track is under 5 percent of the total, but against a 2 Mbps camera feed it is closer to 16 percent.
Divide the capacity by the bitrate. ECMA-267 gives a single-layer DVD 4.7 GB and a dual-layer 8.5 GB; a Blu-ray holds a nominal 25 GB single-layer or 50 GB dual-layer. At 7 Mbps a DVD-5 takes roughly 89 minutes, while a BD-25 at the same rate would run nearly eight hours - which is why disc authoring raises the bitrate rather than the running time.