How to use this calculator
- Enter or choose average bitrate (video + audio).
- Enter or choose video length.
- Enter or choose average share watched.
- Enter or choose plays.
- Enter or choose peak concurrent viewers.
- The total data transferred updates as you type. Use Copy result or Share to keep it.
Method
Bytes per play = Mbps × 10⁶ × Seconds watched ÷ 8; Total GB = Bytes per play × Plays ÷ 10⁹; Peak Gbps = Concurrent viewers × Mbps ÷ 1,000
- Mbps
- average stream bitrate in megabits per second
- Seconds watched
- length × share watched
Worked example
- Per play: 5,000,000 bits/s × 3,600 s = 18 × 10⁹ bits ÷ 8 = 2.25 × 10⁹ bytes = 2,250 MB.
- 1,000 plays × 2.25 GB = 2,250 GB (2.25 TB); × 0.02 = 45.
- Peak: 200 viewers × 5 Mbps = 1,000 Mbps = 1 Gbps.
A one-hour 5 Mbps video watched 1,000 times transfers 2,250 GB, and 200 simultaneous viewers need 1 Gbps.
What the result means
Adaptive streaming switches between bitrates, so use the average delivered bitrate from your analytics, not the top rendition. Peak Gbps sizes origin and CDN capacity; total GB sizes the bill.
Assumptions and limits
- The bitrate is constant across the stream.
- Protocol overhead (segments, TCP/IP headers) typically adds a few per cent to the data transferred.
Questions
Why divide by 8?
Bitrates are quoted in bits per second, and data volumes in bytes. One byte is 8 bits.