About 15-25 Mbps sustained, which is roughly 7 GB an hour. Sustained is the operative word: a connection that peaks at 300 Mbps in a speed test but drops for two seconds every few minutes will still freeze a 4K feed, because live segments arrive continuously with only a few seconds of buffer behind them. Measure during the hour you normally watch rather than at midday. If two people stream 4K at once, double the figure before comparing it against your line. A 1080p feed at 5-8 Mbps is the sensible fallback and frequently the steadier watch on a shared connection.

1. 14K: 15-25 Mbps sustained, ~7 GB per hour
2. 21080p: 5-8 Mbps sustained, ~3 GB per hour
3. 3Two concurrent 4K streams need roughly double the headroom

Check before you buy anything, because software decoding a 4K HEVC stream on stick-class hardware produces heat and dropped frames rather than a picture. The Fire TV Stick 4K and 4K Max both decode HEVC in hardware; only the Max adds AV1, and it carries 2 GB of memory against 1.5 GB. Older televisions are the usual gap: a set without HEVC gives you audio and a black picture on lines that use it, which reads as an app bug and is not one. A 4K player cannot decode what the silicon underneath it refuses.

1. 1Audio with no picture is a classic missing-codec signature
2. 2Hardware decode keeps the device cool; software decode does not

More than people expect. The HDMI input has to be running in its high-bandwidth mode, which on many televisions is a per-input setting buried under a name like enhanced or deep color, and which is off by default. Output resolution set to auto can settle on 1080p60 after a handshake hiccup and stay there quietly. Cables matter at 4K60 in a way they do not at 1080p, and a long unbranded cable is a real failure mode. Work down this chain before touching the app: input mode, output resolution, cable, then the player. Most soft 4K pictures are a negotiation, not a stream.

1. 1Enable the input's high-bandwidth HDMI mode on the television
2. 2Set output resolution by hand instead of leaving it on auto

It depends on your viewing distance and your connection, and the honest answer for many households is no. At normal seating distance on a set under about 55 inches, the visible gain over a clean 1080p feed is small, while the bandwidth requirement roughly triples and the data cost more than doubles. A steady 1080p picture beats a 4K one that stalls twice a match. Where 4K earns its place is a large panel, a wired connection with headroom, and content that was actually produced at that resolution rather than upscaled somewhere along the way.

1. 1Large panel plus wired connection: 4K is worth it
2. 2Shared Wi-Fi or a metered line: a clean 1080p feed wins

Do the arithmetic before you commit, because it surprises people. At about 7 GB an hour, three hours of 4K viewing a day is roughly 630 GB a month from one screen. Two screens doing the same land near 1.26 TB, which is at or above the cap some home connections still carry. The same viewing at 1080p costs about 3 GB an hour, or roughly 270 GB a month per screen. Mixing the two, with 4K reserved for the events you care about and 1080p for background viewing, keeps the total manageable without giving up the picture where it counts.

1. 1One screen, three hours a day of 4K: about 630 GB a month
2. 2The same at 1080p: about 270 GB a month