Video Bitrate & Aspect Ratio Calculator
Calculate video bitrates, file sizes, Discord/email compression targets, and aspect ratio scaling.
How to use this tool & FAQs
Click any question below to expand its guide and answer
How Video Bitrate & Aspect Ratios Work
Video file size is determined almost entirely by encoding bitrates, regardless of pixel resolution:
1. The Video File Size Formula
- Total File Size (Bits) = (Video Bitrate + Audio Bitrate) × Duration in Seconds
- File Size (Bytes) = Total Bits ÷ 8
- File Size (Megabytes) = Total Bytes ÷ (1024 × 1024)
2. Staying Under Platform Limits (Discord, WhatsApp, Email)
When sending videos through platforms with strict upload limits (such as Discord's 25MB free limit or WhatsApp's 16MB document cap), use the Target Size to Bitrate mode. It calculates the maximum combined bitrate your rendering software (Premiere Pro, HandBrake, FFmpeg) should use so the exported file never gets rejected.
3. Why Video Dimensions Must Be Even Numbers
Modern video compression codecs (H.264 / AVC, H.265 / HEVC, VP9, AV1) divide frames into 2×2 or 16×16 pixel macroblocks for 4:2:0 YUV chroma subsampling. An odd width or height (e.g. 1081px) will cause rendering errors or black border distortion. This calculator automatically snaps all scaled dimensions to the nearest even integer.
Frequently Asked Questions
What bitrate should I use for 1080p 60fps on YouTube?
YouTube officially recommends 12,000 kbps (12 Mbps) for 1080p 60fps video and 8,000 kbps (8 Mbps) for standard 30fps video, with 128 to 384 kbps stereo audio.
Does lowering resolution decrease file size?
Not necessarily! If you reduce resolution from 4K to 720p but keep the bitrate at 20,000 kbps, the file size remains exactly the same. File size is determined by bitrate × duration, not pixel count.