Fiber-to-the-home is now the default fixed connection in Spain, but the speed debate is still shaped by marketing rather than real workloads. The CNMC’s statistics note, published on 23 September 2026, reported 18.3 million FTTH lines in July, within a fixed broadband market that passed 20 million lines for the first time. For most households, the practical answer is less capacity than the latest advert suggests.
- 4K streaming: Netflix requires 15 Mbps and YouTube 20 Mbps per screen.
- Video calls: Teams recommends 4 Mbps down and 2.5 Mbps up, or 4 Mbps up for best performance.
- Demanding total: A multi-screen home can peak near 48 Mbps down, leaving room on a 100 Mbps line.
- Real bottleneck: Wi-Fi, upload speed and stability matter more than the headline gigabit rate.
What each activity actually needs
Streaming and video-call services publish their own requirements, and none asks for more than 20 Mbps per screen at top quality. Netflix lists 3 Mbps for HD 720p, 5 Mbps for Full HD 1080p and 15 Mbps for 4K. YouTube lists 2.5 Mbps for 720p, 5 Mbps for 1080p and 20 Mbps for 4K. Microsoft Teams recommends 4 Mbps downstream and 2.5 Mbps upstream for video, rising to 4 Mbps upstream for best performance.
The nuance matters more than the raw numbers. Netflix refers to a stable connection and YouTube to constant speed: a 600 Mbps spike is useless if the line drops every few minutes. Microsoft adds that Teams is conservative with bandwidth and can deliver HD video below 1.5 Mbps, prioritising audio when capacity is scarce.
Do the household math—and check upload
Add up simultaneous activity at the worst moment of the day, not across the whole day. A demanding example: one TV running Netflix in 4K at 15 Mbps, another running YouTube in 4K at 20 Mbps, two people on Teams video calls at 8 Mbps down and 5 Mbps up, and a third device streaming a 1080p series at 5 Mbps. The downstream total is about 48 Mbps. That is a heavy load, and a 100 Mbps line still leaves ample headroom.
Paying for 1 Gbps can make sense for households that frequently move very large files, have many intensive users, or face a minimal price gap. For streaming and remote work, the jump is more visible on the bill than on the screen. Upload deserves closer scrutiny: video calls, cloud backups and sending video files depend on it, and the example above already needs 5 Mbps upstream just for Teams.
Before signing, review the contract summary. Article 67 of Spain’s General Telecommunications Law requires the operator to provide it before contracting and to include, for fixed connections, the minimum, normally available, maximum and advertised speeds for both download and upload. The advertised figure is only one of the four—and the most optimistic.
Why the fiber feels slower: Wi-Fi is the usual suspect
Contracted speed reaches the router, not the sofa. Wi-Fi performance depends on distance, walls, interference, the band each device uses and router configuration. YouTube notes that a wired connection can be useful for films, series and live streams. Netflix suggests testing from the device you will use, via Fast.com in a browser or the TV app. If a wired test matches the plan and a Wi-Fi test delivers half, the bottleneck is local.
Apple’s recommended router settings highlight the most impactful fixes: enable every available band—2.4, 5 and 6 GHz—under the same network name, because separate names can stop devices from choosing the best one; keep 2.4 GHz on 20 MHz channels and 5/6 GHz on automatic width; avoid legacy WEP or TKIP security, which is insecure and reduces performance, in favour of WPA3 or WPA2/WPA3 transition mode; and keep router firmware updated. A DNS change can also improve browsing speed and privacy in as little as two minutes.
If Wi-Fi remains poor after those checks, router placement or home coverage is usually the issue. The gigabit race in fiber advertising is more marketing than domestic necessity. The requirements published by Netflix, YouTube and Microsoft show that a normal household fits comfortably within 100 or 300 Mbps, and that experience depends far more on line stability, upload capacity and well-built Wi-Fi. Before paying more each month for speed the Wi-Fi will not deliver, spend an afternoon reviewing the router or improving coverage in a large home. When comparing offers, compare the minimum speed in the contract summary, not the headline number. It is the figure that says something about what you will receive on a Tuesday at nine in the evening.