Where the numbers come from
| Activity | Published requirement | Source |
|---|---|---|
| 4K / UHD stream | 15 Mbps or higher | Netflix |
| 4K stream on YouTube | 20 Mbps sustained | YouTube |
| 1080p stream | 5 Mbps (Netflix and YouTube) | Netflix, YouTube |
| 1080p group video call | 3.8 Mbps up, 3.0 Mbps down | Zoom |
The calculator uses Netflix's 15 Mbps for 4K. If most of your 4K watching is YouTube, add one extra HD stream per 4K stream to cover the difference. Sources were checked on 2026-11-04.
Why add headroom?
The published figures are what a single stream needs once it is running. Real homes add phones syncing photos, game updates and other traffic, and speeds dip at busy times. Headroom is our assumption, not a published standard, which is why you can set it to zero. We default to 25% because a link that is completely full also tends to get much higher latency.
Upload is usually the tighter limit
Streaming barely uses upload, but every video call sends as well as receives. On cable plans with 10–20 Mbps upload, three people on 1080p calls at once (11.4 Mbps of upload by Zoom's numbers) plus a cloud backup can saturate the upstream. If calls stutter while downloads look fine, read why upload speed is so often the problem.