The margin (typically 30–50%) accounts for the fact that real internet connection speed fluctuates and doesn't always reach the maximum advertised by your ISP — the recommended speed is set above the bare minimum specifically to avoid buffering.
Result
This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.
Facts and limits of this method
| SD (480p) | ≈3 Mbps per stream |
|---|---|
| HD (720p) | ≈5 Mbps per stream |
| Full HD (1080p) | ≈8 Mbps per stream |
| 4K Ultra HD (2160p) | ≈25 Mbps per stream |
| Formula | recommended speed = bitrate × streams × (1 + margin/100) |
When it misleads you
- The bitrate figures given are typical benchmarks for major streaming platforms; a specific service may use adaptive bitrate that automatically adjusts to available connection speed, so actual usage may differ.
- The calculation assumes all listed streams use the same quality — if devices are watching different quality video simultaneously, use "custom bitrate" mode and sum the values manually, or run several separate calculations.
- Connection speed isn't the only factor in uninterrupted streaming — latency (ping), connection stability, and how busy your ISP's network is at a given time also matter.
- The margin for speed fluctuations is a simplified adjustment, not a guarantee: on a strongly unstable connection, even the recommended speed may not be enough for fully uninterrupted playback.
How it is calculated
For the selected video quality, a typical recommended bitrate per stream is used (or the manually entered value when "custom bitrate" is selected).
The minimum required connection speed is computed as the bitrate per stream multiplied by the number of simultaneous streams.
The recommended speed is additionally increased by the margin percentage, to account for fluctuations in real connection speed and avoid video buffering.
All three values — recommended speed, minimum speed and bitrate per stream — update instantly whenever any parameter changes.
Questions and answers
Why is the recommended speed higher than the minimum required?
Because real internet connection speed fluctuates and rarely stays consistently at the advertised maximum — the margin helps avoid video buffering even during a temporary speed drop.
How do I calculate the speed for several people watching video simultaneously on different devices?
Enter the total number of simultaneous streams in the corresponding field — the calculator multiplies one stream's bitrate by that number to get the total required speed.
Where do the bitrate values for each quality level come from?
They're averaged benchmarks close to the recommendations of major streaming services for the corresponding resolution — a specific platform may use somewhat different values depending on codec and compression settings.
Is my data sent anywhere?
No, the whole calculation runs in your browser.