4K, or Ultra HD, has four times the pixels of Full HD. Thanks to modern compression codecs like HEVC and AV1, streaming services don't need four times the data, but 4K still typically uses around 7 GB per hour — compared to about 3 GB for HD. Some services and titles with HDR or Dolby Vision can use even more during peak scenes.
For a household watching three hours of 4K per evening, that adds up to about 630 GB per month. Add a second TV streaming at the same time and you can easily pass a terabyte. Many home internet plans are unlimited, but some fibre, cable and especially mobile or 5G home internet plans have data caps or fair-use limits.
You also need enough speed: most services recommend at least 15–25 Mbps for a stable 4K stream, per device. If your connection is slower, the service will automatically drop to a lower resolution, which reduces data use but also picture quality.
Is 4K worth it? On a large TV viewed from a normal distance, the improvement is clear, especially with HDR. On a phone, tablet or small monitor, the visible difference is minimal, so choosing HD on those devices can save a lot of data without compromising your experience.
The calculator above is pre-filled with 4K streaming on two services. Change the number of devices or hours to see how quickly Ultra HD adds up and which data plan you'd need.