Bitrate
How much data each second of video carries — the single biggest lever on how sharp your video looks and how much bandwidth it costs.
Bitrate is how many bits of data are spent on each second of video — turn it up and the picture sharpens but the file and bandwidth bill grow; turn it down and it shrinks but can go blocky.
What is bitrate?
Bitrate is the amount of data used to represent one second of video, measured in bits per second — usually kilobits (kbps) or megabits (Mbps). A higher bitrate means more data spent per second, which generally means more detail and a larger file; a lower bitrate means a smaller file that can look soft or blocky if pushed too far.
It is the core lever behind streaming quality. Two videos at the same resolutionResolutionThe pixel dimensions of a video frame — 480p, 720p, 1080p, 2160p (4K). Determines how sharp the picture looks on a given screen.Open definition → can look completely different depending on bitrate: a 1080p clip starved of bitrate will show compression artifacts, while the same clip at a healthy bitrate looks crisp. The codecCodecThe algorithm that compresses and decompresses video — H.264, H.265 (HEVC) and AV1 are the most common in modern streaming.Open definition → matters too — modern codecs achieve the same quality at a lower bitrate.
Recommended bitrate by resolution
Industry-standard target bitrates for H.264 (AVC) encoding. H.265 and AV1 achieve similar quality at roughly half these values.
| Resolution | Name | Min bitrate | Recommended |
|---|---|---|---|
| 360p | SD | 300 kbps | 500–800 kbps |
| 480p480pStandard-definition video, 480 pixels tall — 854×480 in 16:9. The fallback rung of the adaptive ladder for slow or metered connections.Open definition → | SD | 600 kbps | 1–1.5 Mbps |
| 720p720pHigh definition at 1280×720 — 921,600 pixels per frame. The entry point to HD and the fallback rung below Full HD.Open definition → | HD | 1.5 Mbps | 2.5–4 Mbps |
| 1080p1080p (Full HD)Full HD at 1920×1080 — just over two million pixels. The default target for course, sales and web video.Open definition → | Full HD | 3 Mbps | 5–8 Mbps |
| 2160p | 4K4K (2160p)Ultra HD at 3840×2160 — four times the pixels of Full HD, and the point where codec choice starts paying for itself.Open definition → | 10 Mbps | 15–25 Mbps |
Highlighted rows are the sweet spot for most audiences.
Bitrate and file size
Bitrate is also what determines how much a video weighs — and therefore what it costs to store and deliver. The rule of thumb is simple:
Rough estimate
File size ≈ bitrate × duration ÷ 8. A 10-minute (600 s) video at 5 Mbps is about 5 × 600 = 3,000 megabits — divide by 8 to get bytes, so roughly 375 MB. Variable bitrate and the audio track shift the real figure, but it's how you sanity-check storage and bandwidth before you commit.
This is also why adaptive streaming saves money at scale: a viewer on a slow connection is served a lower-bitrate rendition, so they pull far less data than a viewer getting full 1080p — and the delivery bill follows the bits actually sent.
CBR vs. VBR, and adaptive streaming
Constant Bitrate (CBR) holds the same data rate across the whole video — predictable, but it wastes data on simple scenes and can starve complex ones. Variable Bitrate (VBR) spends more on complex scenes and less on simple ones, giving better quality per megabyte.
Adaptive bitrateAdaptive Bitrate (ABR)Automatically adjusts video quality in real time to match each viewer’s connection speed — smooth playback from 480p to 4K with no buffering.Open definition → streaming adds another layer: the video is encoded at several bitrates (a rendition ladder), and the player switches between whole renditions in real time to match each viewer's bandwidth — preventing bufferingBufferingWhen playback pauses to load more data. ABR exists largely to prevent it by stepping quality down before the buffer empties.Open definition → on slow connections while serving maximum quality on fast ones.
Further reading
- Bit rate — Wikipedia — a vendor-neutral overview.
