Video Bitrate & File Size Calculator
Calculate expected export file sizes from duration and bitrate, or find the exact video bitrate required to fit under Discord, email, and social media upload limits.
Platform Upload Bitrate Guide
| Platform & Resolution | Video Bitrate | Audio |
|---|---|---|
YouTube 1080p (Standard) Standard frame rate (24-30 fps) SDR upload recommendation. | 8 Mbps | 384k |
YouTube 1080p (High Frame Rate / HDR) 60 fps SDR or 24-30 fps HDR video recommendation. | 12 Mbps | 384k |
YouTube 4K UHD (Standard) 4K 2160p at 24-30 fps standard SDR recommendation. | 45 Mbps | 384k |
YouTube 4K UHD (60fps / HDR) 4K 2160p at 50/60 fps or HDR video recommendation. | 68 Mbps | 384k |
YouTube 1440p (2K) 1440p standard 24-30 fps video recommendation. | 16 Mbps | 384k |
TikTok / IG Reels (1080p) 1080×1920 vertical video optimized for mobile feed delivery. | 6 Mbps | 192k |
Twitch 1080p 60fps Recommended maximum ingest bitrate for Twitch standard streams. | 6 Mbps | 160k |
Discord Free (Max Quality 1080p) Compact web delivery for short sharing clips. | 2.5 Mbps | 128k |
Common File Size Ceilings
| Target Platform | Hard Limit |
|---|---|
Discord Default free attachment limit on Discord desktop & mobile. | 10 MB |
Discord Common 25MB attachment limit for email & Nitro Basic. | 25 MB |
Discord / Slack Slack free workspace upload & standard clip size. | 50 MB |
Email Safe ceiling for Gmail (25MB limit with Base64 encoding overhead). | 20 MB |
Twitter / X Standard direct web upload ceiling for videos up to 140s. | 512 MB |
Frequently asked questions
How do I calculate video file size from bitrate and duration?
Multiply the total bitrate (video kbps + audio kbps) by duration in seconds, then divide by 8 to convert kilobits to kilobytes. For example, a 60-second video at 8,000 kbps video + 192 kbps audio equals (8,192 × 1,000 × 60) ÷ 8 = 61.44 MB. We also add a ~2% buffer for MP4/MKV container muxing overhead.
What video bitrate should I use for YouTube 1080p and 4K?
YouTube recommends 8 Mbps (8,000 kbps) for 1080p standard frame rates (24-30 fps) and 12 Mbps for 60 fps / HDR. For 4K UHD, YouTube recommends 35-45 Mbps for 24-30 fps and 53-68 Mbps for 60 fps / HDR.
How do I compress a video to fit Discord's 25 MB or 50 MB limit?
Switch the calculator above to 'Target Bitrate from Size', select 25 MB (or 50 MB), and enter your video's exact duration. The calculator will provide the exact video bitrate (in kbps or Mbps) to set in your export settings in Premiere Pro, DaVinci Resolve, or Handbrake.
What is the difference between CBR and VBR encoding?
CBR (Constant Bitrate) encodes every second at the exact same data rate regardless of image complexity. VBR (Variable Bitrate) dynamically allocates more bits to high-action scenes and fewer bits to static shots, achieving higher overall visual quality for the same average file size.
Why is my exported video slightly larger than calculated?
File containers (MP4, MOV, WebM), audio stream overhead, subtitle tracks, and encoder bitrate fluctuation can cause slight variance (~1-3%). Always leave a small safety margin if you are aiming for a strict upload ceiling.