YouTube error · Common
YouTube too slow on cellular — fix the mobile-data experience
YouTube's mobile experience is dramatically worse on cellular than on Wi-Fi. Videos take 10+ seconds to start, quality is locked at 480p, audio cuts out. Wi-Fi at the same speed test number works fine.
Why this happens
- Mobile carrier throttling video traffic specifically.
- Cellular DNS resolves to a different (slower) CDN edge.
- YouTube's "Save data" mobile setting is on.
- Background app refresh is using your bandwidth.
- Roaming on an international SIM with bad CDN peering.
How to fix it
- 1
Test cellular at fast.com
fast.com is Netflix's speed test designed to measure throughput from video CDNs. If general speedtest.net shows 50 Mbps but fast.com shows 5 Mbps on the same cellular, your carrier is throttling video specifically.
- 2
Switch carrier DNS to 1.1.1.1
iOS: Settings → Wi-Fi (or Cellular) → DNS. Android: depends on manufacturer. Forces queries through Cloudflare DNS which often returns faster CDN edges than carrier DNS.
- 3
Turn off Data Saver
YouTube settings → Data saving → off. Make sure it's off for cellular specifically.
- 4
Download on Wi-Fi for offline cellular use
If carrier throttling is unavoidable, downloading on Wi-Fi and watching offline bypasses the cellular bandwidth issue entirely.