Streaming Bandwidth Calculator Widget
Size a live stream from both ends. Concurrent viewers times the average bitrate they watch gives peak egress and the gigabytes or terabytes a CDN will bill; the bitrate you send, the number of outgoing streams and a safety margin give the upload speed your connection must sustain.
Live preview
Under the widget on your page: Powered by A2Z Tools
Embed code
<iframe src="https://a2z.tools/embed/w/streaming-bandwidth-calculator" title="Streaming Bandwidth Calculator by A2Z Tools" width="100%" height="640" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="streaming-bandwidth-calculator" data-height="640"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
Every viewer receives their own copy of the stream, so delivery bandwidth scales with the audience: 500 concurrent viewers watching an average of 4.5 Mbps need 2,250 Mbps, or 2.25 Gbps, from the server or CDN. Multiplying by 3,600 seconds and dividing by 8 converts that rate into data - 1,012.5 GB, about 1.01 TB, every hour, and 2.03 TB for a two-hour event. With adaptive bitrate, enter the average of the renditions people actually watch, not the top one. The streamer's side is different: it sends one stream, or several when it encodes multiple renditions or simulcasts to more than one platform itself. The OBS Project's connection guide suggests a bitrate of about 75% of total upload speed, leaving headroom for other traffic and fluctuations, so a 6 Mbps stream needs about 8 Mbps of upload. The share is adjustable from 10% to 100%. Decimal units are used: 1 GB is 10^9 bytes.
Calculation method
- Egress (Mbps) = concurrent viewers x average delivered bitrate
- Data per hour (GB) = egress (Mbps) x 3,600 / 8 / 1,000
- Data per event = data per hour x event length in hours
- Upload needed = stream bitrate x outgoing streams / (share of upload used, e.g. 0.75)
Worked examples
Self-hosted event
Inputs: 500 viewers; 4.5 Mbps average; 2 hours; sending 6 Mbps; 75% of upload
Result: 2.25 Gbps egress; 1.01 TB per hour; 2.03 TB in total; 8 Mbps upload
2,250 Mbps x 3,600 / 8 = 1,012,500 MB per hour.
Sending three renditions
Inputs: 6 Mbps each; 3 streams; 80% of upload
Result: 22.5 Mbps upload needed
18 Mbps sent / 0.8.
Limitations
- Ignores protocol overhead (a few percent) and retransmissions on poor networks.
- Assumes every viewer watches for the whole event; real audiences come and go, so data per event is an upper estimate.
- Does not price the data - CDN rates differ by provider, region and volume.
Where publishers use it
- A church or school planning to self-host a weekly service or assembly stream
- An esports organiser budgeting CDN costs for a tournament weekend
- A streaming-setup guide that tells new streamers which internet plan they need
- A conference AV company quoting a hybrid event
- An ISP's business-broadband page aimed at live producers
Questions
Do I pay for viewer bandwidth on YouTube or Twitch?
No - those platforms deliver the stream to viewers on their own networks, so only your upload matters. Viewer egress becomes your cost when you self-host, use a paid CDN or a video platform that bills by gigabytes delivered.
How much upload speed do I need to stream?
The OBS Project suggests setting the stream bitrate to about 75% of your total upload speed. A 6 Mbps stream therefore wants about 8 Mbps of upload, and a 4.5 Mbps stream about 6 Mbps. Test upload at the time of day you stream, because shared connections slow down in the evening.
What if I send several renditions or simulcast?
Each extra stream you send from your own connection adds its full bitrate. Simulcasting a 6 Mbps stream to three platforms yourself means 18 Mbps out, which at a 75% share needs 24 Mbps of upload. Cloud restreaming services avoid this by fanning out on their side.
What bitrate should I stream at?
YouTube Help's live encoder table recommends, for H.264, about 8 Mbps for 720p60 and 17 Mbps for 1080p60, with lower figures for AV1 and HEVC. Platforms also cap ingest bitrates, so check your platform's current limits.
Why use concurrent viewers rather than total views?
Bandwidth is a rate: what matters is how many people watch at the same moment. 5,000 total views spread over a two-hour stream might peak at 1,500 concurrent viewers. Use the peak to size capacity and the average to estimate data.
Sources
- Stream Connection Troubleshooting - OBS Project . Advises that a good starting point is a bitrate of 75% of total upload speed. Checked 2026-10-01.
- Choose live encoder settings, bitrates, and resolutions - YouTube Help (Google) . Recommended live ingest bitrates by resolution and codec, e.g. H.264 1080p60 about 17 Mbps; advises running a speed test of upload bitrate. Checked 2026-10-01.
Cite or recommend this tool
If you reference this tool in an article, course or documentation, these formats are ready to copy. They are optional - nothing is added to your site unless you paste it.
A2Z Tools Streaming Bandwidth Calculator https://a2z.tools/embed/streaming-bandwidth-calculator
<a href="https://a2z.tools/embed/streaming-bandwidth-calculator">A2Z Tools Streaming Bandwidth Calculator</a>
[A2Z Tools Streaming Bandwidth Calculator](https://a2z.tools/embed/streaming-bandwidth-calculator)
Streaming Bandwidth Calculator by A2Z Tools - https://a2z.tools/embed/streaming-bandwidth-calculator
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