Creator media glossary
What is bitrate?
Short answer
How much data a video or audio file uses per second of playback, usually measured in Mbps (video) or kbps (audio).
Key takeaways
- Bitrate is how much data a video or audio stream uses per second, in Mbps or kbps.
- File size = bitrate × duration ÷ 8 (Mbps × seconds ÷ 8 = megabytes).
- YouTube recommends 8 Mbps for 1080p at 30 fps and 12 Mbps at 60 fps; the Instagram API caps uploads at 25 Mbps.
- Use variable bitrate (VBR) or a quality setting (CRF) for uploads; constant bitrate is for live streaming.
Bitrate explained
Bitrate is the single biggest lever on file size. At a fixed resolution and frame rate, doubling the bitrate roughly doubles the file size and - up to a point - visibly improves quality, because more data means less compression artifacting per frame.
Past a certain point, more bitrate stops helping: platforms re-encode everything you upload to their own target bitrate anyway, so a wildly over-bitrated source file mostly just makes the upload slower without changing what viewers eventually see.
Bitrate units: kbps, Mbps and MB/s
Bitrate is measured in bits per second. Video is usually quoted in megabits per second (Mbps, millions of bits) and audio in kilobits per second (kbps, thousands). File sizes and download speeds in apps are often in bytes, and one byte is eight bits, so 8 Mbps is 1 megabyte per second. Mixing up Mb and MB is the most common reason file-size estimates come out eight times wrong.
| Example | Bitrate | Per minute |
|---|---|---|
| CD audio (uncompressed, 44.1 kHz, 16-bit stereo) | 1,411 kbps | About 10.6 MB |
| MP3 at its highest standard setting | 320 kbps | About 2.4 MB |
| AAC stereo, Instagram API spec | 128 kbps | About 1 MB |
| YouTube 1080p SDR upload at 24-30 fps | 8 Mbps | About 60 MB |
| YouTube 4K SDR upload at 24-30 fps | 35-45 Mbps | About 260-340 MB |
| Apple ProRes 422 HQ, 1080p at 29.97 fps | About 220 Mbps | About 1.6 GB |
Per-minute sizes are bitrate × 60 ÷ 8, rounded. ProRes figure from Apple's ProRes white paper.
CBR, VBR, ABR and CRF: bitrate modes
Constant bitrate (CBR)
The same number of bits every second, whether the scene is a still title or confetti. Predictable for live streaming over a fixed connection, but wasteful for files: simple scenes get more than they need and complex ones too little.
Variable bitrate (VBR)
The encoder spends more on complex scenes and less on simple ones around a target average, often with a maximum. Two-pass VBR analyzes the whole video first and hits the target size most accurately. YouTube and the Instagram API both ask for VBR uploads.
Average bitrate (ABR)
A single-pass compromise that aims at an average without the first analysis pass. Common in quick exports and some streaming encoders.
Constant quality (CRF, CQ)
Instead of a bitrate you choose a quality level and let the size fall where it may. In x264 and x265, CRF runs from 0 (lossless) to 51 and lower is better; the default is 23 in x264 (28 in x265), and 18-20 in x264 looks close to the source. Best for masters and archive copies where size is not fixed.
Bitrate, resolution and frame rate together
Bitrate is spread across every pixel of every frame, so the useful measure is bits per pixel: bitrate ÷ (width × height × frames per second). YouTube's 8 Mbps for 1080p at 30 fps works out to about 0.13 bits per pixel. Double the frame rate or move to 4K at the same bitrate and each pixel gets far less, which shows up as blocky motion and smeared detail. That is why recommended bitrates climb with resolution and frame rate, and why fast, detailed scenes such as sport, confetti or water need more than talking heads.
YouTube's recommended upload bitrates (SDR)
| Quality | 24-30 fps | 48-60 fps | Video per minute at 24-30 fps |
|---|---|---|---|
| 8K | 80-160 Mbps | 120-240 Mbps | about 600-1200 MB |
| 2160p (4K) | 35-45 Mbps | 53-68 Mbps | about 263-338 MB |
| 1440p (2K) | 16 Mbps | 24 Mbps | about 120 MB |
| 1080p | 8 Mbps | 12 Mbps | about 60 MB |
| 720p | 5 Mbps | 7.5 Mbps | about 38 MB |
| 480p | 2.5 Mbps | 4 Mbps | about 19 MB |
| 360p | 1 Mbps | 1.5 Mbps | about 8 MB |
Bitrates: YouTube Help: Recommended upload encoding settings, checked 2026-10-05. Megabytes per minute computed as Mbps × 60 ÷ 8.
Why higher bitrate is not always better
Platforms re-encode every upload into their own streaming versions. Above the recommended bitrate you mostly make the upload slower; below it, the platform starts from a damaged source and the loss compounds.
Bitrate needed for a given quality also depends on the codec: newer codecs such as HEVC and AV1 reach similar quality at lower bitrates than H.264.
File size from bitrate, worked out
| Video bitrate | 30 seconds | 1 minute | 10 minutes |
|---|---|---|---|
| 4 Mbps | 15 MB | 30 MB | 300 MB |
| 8 Mbps | 30 MB | 60 MB | 600 MB |
| 12 Mbps | 45 MB | 90 MB | 900 MB |
| 25 Mbps | 94 MB | 188 MB | 1.9 GB |
| 45 Mbps | 169 MB | 338 MB | 3.4 GB |
Video only, in decimal megabytes; add about 1.4 MB per minute for 192 kbps audio. Our compression ratio calculator works it out for any file.
Audio bitrate
| Audio | Typical bitrate | Notes |
|---|---|---|
| Voice, podcasts (AAC or MP3) | 64-128 kbps | Mono is enough for a single speaker |
| Music streaming (AAC, Vorbis, Opus) | 128-320 kbps | Opus sounds good from about 96 kbps stereo |
| YouTube upload, stereo | 384 kbps | YouTube recommendation |
| FLAC (lossless CD quality) | About 700-1,000 kbps | Varies with the music |
| WAV (uncompressed 48 kHz, 24-bit stereo) | 2,304 kbps | Editing and mastering |
How to check and change bitrate
- Check: Windows File Explorer > Properties > Details shows "Total bitrate"; on a Mac, QuickTime Player > Window > Show Movie Inspector shows the data rate; MediaInfo and our file checker show it per stream.
- Change: in an editor's export settings, pick VBR with a target and maximum, or a quality (CRF) setting.
- Shrink a file without changing resolution by re-encoding at a lower bitrate; our compressor does this in the browser.
- Do not raise the bitrate of an already compressed file: re-encoding at 50 Mbps cannot restore detail lost at 5 Mbps.
Free tools:Video compressorFile inspectorCompression ratio calculator
Frequently asked questions
What is bitrate in simple terms?
Bitrate is how much data a file uses for each second of playback: video in megabits per second (Mbps), audio in kilobits per second (kbps). More bitrate means more detail can survive compression, and a larger file.
How do I work out file size from bitrate?
Size in megabytes = bitrate in Mbps × duration in seconds ÷ 8. A 60-second clip at 8 Mbps is 8 × 60 ÷ 8 = 60 MB of video, plus audio (384 kbps stereo adds about 3 MB a minute).
What is a good bitrate for 1080p?
YouTube recommends 8 Mbps for 1080p at 24-30 fps and 12 Mbps at 48-60 fps (SDR). The Instagram API caps uploads at 25 Mbps, so 8-12 Mbps fits both.
Constant or variable bitrate?
Variable (VBR) for uploads: it spends bits on complex scenes and saves them on simple ones. YouTube asks for variable bitrate and says no bitrate limit is required; the Instagram API also specifies VBR, 25 Mbps maximum.
What audio bitrate should I use?
YouTube recommends 128 kbps for mono, 384 kbps for stereo and 512 kbps for 5.1. The Instagram API lists 128 kbps AAC.
Is a higher bitrate always better?
Up to a point. Below the recommended rate, quality falls fast; above it, gains become invisible while files and uploads grow. Platforms re-encode to their own bitrates anyway.
What is the difference between bitrate and bandwidth?
Bitrate is how much data a stream uses per second; bandwidth is how much a connection can carry. A stream plays smoothly only when the bandwidth comfortably exceeds the bitrate.
Let Koldflux pick the settings
Koldflux chooses the codec, container and bitrate for each platform when it exports.
Free tools that use this
Sources and how we checked
- YouTube Help: Recommended upload encoding settings (checked 2026-10-05)
- Instagram API: IG User Media (reel, story and video specifications) (checked 2026-10-05)
- MDN: Web video codec guide (checked 2026-10-05)
- Apple: Apple ProRes white paper (checked 2026-10-06)
Reviewed October 6, 2026 by the Koldflux team. Definitions follow the specifications and platform documentation linked above; platform tables come from the same registry the Koldflux tools use.