Bitrate is the single most misunderstood variable in video production. Too low, and your carefully color-graded footage looks like compressed soup — muddy details, blocky motion, color banding in gradients. Too high, and you are generating files so large that delivery platforms re-compress them anyway, your editor crawls on proxy footage, and storage costs compound. Finding the right bitrate for your resolution, codec, and delivery target is both a technical decision and a practical one, and the math for calculating file sizes is simple once you know the formula.
What Is Bitrate and Why It Matters
Bitrate is the amount of data delivered to the decoder per second — measured in kilobits per second (Kbps) or megabits per second (Mbps). It determines how much information is available to represent each frame of video.
Higher bitrate means more data per frame, which means finer detail, smoother gradients, better motion handling, and less compression artifacting. But it is a diminishing returns relationship: doubling the bitrate from 5 Mbps to 10 Mbps produces a visible quality improvement, while doubling from 40 Mbps to 80 Mbps produces a much smaller visible improvement at typical viewing distances and screen sizes.
The critical distinction: bitrate for capture/editing versus bitrate for delivery are entirely different targets. Camera footage for editing might run at 400–800 Mbps (RAW or ProRes). Edited footage exported for a client might run at 50–100 Mbps. The final version uploaded to YouTube might run at 15–35 Mbps. Each stage has different requirements.
Recommended Bitrate by Resolution
The table below covers standard delivery encoding targets — not camera capture specifications. These are appropriate for client deliverables, archival masters, and platform uploads.
| Resolution | Frame Rate | H.264 Bitrate | H.265/HEVC Bitrate | Use Case |
|---|---|---|---|---|
| 720p | 24/25/30 fps | 4–6 Mbps | 2.5–4 Mbps | Web delivery, older devices |
| 720p | 60 fps | 6–9 Mbps | 4–6 Mbps | Gaming, sports web content |
| 1080p | 24/25/30 fps | 8–12 Mbps | 5–7 Mbps | Standard HD delivery |
| 1080p | 60 fps | 12–18 Mbps | 7–10 Mbps | Sports, gaming, high-motion |
| 4K (UHD) | 24/25/30 fps | 35–50 Mbps | 18–28 Mbps | 4K streaming master |
| 4K (UHD) | 60 fps | 50–65 Mbps | 28–40 Mbps | 4K sports, action |
| 4K (DCI) | 24/25 fps | 50–70 Mbps | 30–40 Mbps | Cinema delivery |
| 8K | 24/25/30 fps | 100–160 Mbps | 55–90 Mbps | Future-proofing archival |
For archival masters intended to be re-edited later, go higher — at or above the upper bound of each range. For delivery files that will be re-encoded by a platform (YouTube, Vimeo, streaming services), hitting the recommended range is sufficient since further data is wasted: the platform's encoder will limit quality to its own output bitrate regardless of how high your upload was.
Codec Comparison: H.264 vs H.265 vs AV1
The codec determines how efficiently each bit of data is used to represent visual information. More efficient codecs achieve the same perceptual quality at lower bitrates — or better quality at the same bitrate.
H.264 (AVC): The most universally compatible codec. Plays natively on virtually every device, browser, smart TV, and media player made in the past 15 years. Higher bitrate requirement for a given quality level versus newer codecs, but hardware decoding support is universal. Best for maximum compatibility.
H.265 (HEVC): Approximately 40–50% more efficient than H.264 at equivalent quality. A 1080p video that looks good at 8 Mbps in H.264 looks equivalent at 5 Mbps in H.265. The tradeoff is compatibility — older browsers, devices, and some streaming platforms lack H.265 support. Hardware decoding support has improved dramatically since 2020. Best for 4K delivery and storage-constrained archival.
AV1: The newest widely-adopted codec, developed by the Alliance for Open Media (Google, Netflix, Amazon, etc.). Approximately 25–30% more efficient than H.265, meaning 30–40% smaller files at equivalent quality versus H.265. Open-source and royalty-free. YouTube and Netflix use it extensively. Hardware encoding support is still limited (though growing fast in 2024–2025 hardware). Software encoding is very slow. Best for platform delivery where you can afford encoding time.
| Codec | Relative Efficiency | Compatibility | Encoding Speed |
|---|---|---|---|
| H.264 | Baseline | Universal | Fast |
| H.265 | ~50% better than H.264 | Good, not universal | Moderate |
| AV1 | ~30% better than H.265 | Growing (web/streaming) | Slow (software) |
| VP9 | Similar to H.265 | Web browsers | Moderate |
CBR vs VBR: Which to Use
Constant Bitrate (CBR): The encoder maintains a fixed bitrate regardless of scene complexity. A slow pan across a solid color wall gets the same data rate as fast-motion camera shake through a crowd.
- Best for: live streaming, broadcast delivery, any situation where the decoder needs a predictable data stream
- Why: streaming protocols buffer based on expected data rates; variable rates can cause buffering events
- Trade-off: wastes bits on simple scenes, may compress complex scenes more than needed
Variable Bitrate (VBR): The encoder allocates more bits to complex scenes (motion, fine detail, high contrast) and fewer bits to simple scenes (static shots, blurred backgrounds).
- Best for: file-based delivery, archiving, download-and-play content
- Why: achieves better average quality at the same average bitrate, or equal quality at lower average bitrate
- Trade-off: unpredictable file sizes, cannot guarantee data delivery rates for live streaming
For YouTube uploads, VBR is preferred. For Twitch and other live streaming, CBR is required by the platform. For client deliverables intended to be archived or re-edited, use VBR with a high target bitrate.
Platform Requirements: YouTube, Twitch, TikTok, Instagram
Each platform has specific upload recommendations and hard limits. Exceeding them is generally fine — the platform re-encodes on ingest — but falling significantly below them degrades your upload quality before the platform's encoder even touches it.
| Platform | Recommended Upload Bitrate | Max Resolution | Frame Rate | Notes |
|---|---|---|---|---|
| YouTube | 35–45 Mbps (4K), 8–12 Mbps (1080p) | 8K | Up to 60 fps | Re-encodes to VP9/AV1 on upload |
| Twitch | 6 Mbps max (partners 8 Mbps) | 1080p60 | 60 fps | CBR required; most viewers at 1080p |
| TikTok | 50 Mbps recommended upload | 4K (limited) | Up to 60 fps | Heavy re-encoding; upload quality matters |
| Instagram Reels | 25–30 Mbps | 1080p | Up to 60 fps | 9:16 aspect ratio, heavy compression |
| Vimeo (Plus+) | No hard limit | 8K | Up to 120 fps | Minimal re-encoding, better quality |
| 8 Mbps (1080p), 35 Mbps (4K) | 4K | Up to 60 fps | Significant re-compression applied |
YouTube's note is important: uploading at very high bitrates (50+ Mbps for 4K) does not mean viewers receive that bitrate. YouTube's delivered bitrate is 15–25 Mbps for 4K streams. However, uploading a high-bitrate master gives YouTube's encoder better source material to work from, resulting in a better final output at their lower delivery bitrate.
File Size Calculator: Minutes × Bitrate
Estimating output file size is straightforward:
File size (MB) = (Bitrate in Mbps × 60 × Duration in minutes) ÷ 8
The division by 8 converts megabits to megabytes (8 bits per byte).
Worked examples:
1080p30, H.264, 10 Mbps, 60-minute documentary:
File size = (10 × 60 × 60) ÷ 8 = 36,000 ÷ 8 = 4,500 MB = 4.5 GB
4K30, H.265, 25 Mbps, 5-minute commercial:
File size = (25 × 60 × 5) ÷ 8 = 7,500 ÷ 8 = 937.5 MB ≈ 1 GB
1080p60, H.264, 16 Mbps, 90-minute wedding film:
File size = (16 × 60 × 90) ÷ 8 = 86,400 ÷ 8 = 10,800 MB = 10.8 GB
For storage planning, assume a typical 2-hour 4K wedding film delivered at 25 Mbps H.265 runs approximately 22–25 GB. The same film at H.264 40 Mbps runs approximately 36 GB. Factor in multiple delivery versions (client copy, social cut, highlight reel) and a single wedding project can require 100–200 GB of total storage across all deliverables and exports.