Video Bitrate Calculator — Target Size to Required Bitrate
A video bitrate calculator works backwards from a file-size budget to the bitrate your encoder should use — the calculation behind “fit this video in 500 MB”.
Quick answer: Bitrate (Mbps) = target size (MB) × 8 ÷ duration (seconds). To fit a 10-minute video in 500 MB you need about 6.7 Mbps; for a 2-minute clip in 50 MB, about 3.3 Mbps.
Formats: 90m · 1h30m · 5400s · plain number = seconds
Typical H.264 average bitrates at medium quality
Overrides the preset when filled — use the target bitrate from your encoder settings
| Duration | Size (decimal GB/MB) |
|---|---|
| 1 min | 37.5 MB |
| 5 min | 187.5 MB |
| 30 min | 1.125 GB |
| 1 h | 2.25 GB |
| 2 h | 4.5 GB |
| 10 h | 22.5 GB |
| Formula | Mbps = MB × 8 ÷ seconds |
|---|---|
| 10 min in 500 MB | ~6.7 Mbps |
| 30 min in 1 GB | ~4.4 Mbps |
| YouTube 1080p upload | ~8 Mbps · 4K upload 35–45 Mbps |
| Twitch 1080p60 | 6,000 kbps recommended, 8,500 kbps ceiling |
Leave headroom above the number
Encoders rarely land exactly on a target: two-pass CBR gets within a few percent, but single-pass VBR and CRF modes drift by 10–30% depending on content. Add 10–20% to the calculated bitrate, or switch to a two-pass encode when a hard size limit matters (attachments, upload portals, embedded players).
Match the bitrate to the platform instead
If the destination is a streaming platform, hitting a size target is the wrong goal: upload at the platform's recommended bitrate and let it re-encode. YouTube's ladder wants about 8 Mbps for 1080p SDR and 35–45 Mbps for 4K; Twitch accepts 6,000 kbps for 1080p60 within an 8,500 kbps ceiling. Uploading above the recommendation wastes time without improving the delivered picture.
Frame rate is part of the bitrate
Doubling the frame rate approximately doubles the bits needed for equivalent quality. If a 4K60 encode must land under a size cap, dropping to 30 fps is a bigger saving than a codec change; if motion smoothness matters, keep 60 fps and lower the resolution instead — the eye is more forgiving of resolution than of stutter.
When to use this calculator
- Fitting a video under a hard size limit for a form or attachment.
- Planning a live stream within an upload bandwidth budget.
- Choosing export settings for a fixed-capacity archive (DVD, SSD, cloud tier).
- Sanity-checking an encoder's output after a two-pass run.