Cable vs Fiber Real-World Speeds: What You Actually Get vs What They Advertise
Fiber customers receive roughly 112% of advertised speed during peak hours. Cable customers receive about 87%. Here is the full data.
Data: FCC Measuring Broadband America 2024, Ookla Speedtest Index Q1 2026. Updated April 2026.
Speed Reality Calculator
Based on FCC Measuring Broadband America 2024 medians. Individual results vary by provider, location, and equipment.
The FCC Data
The FCC Measuring Broadband America program measures actual delivered speeds from ISP customers using Whiteboxes installed in homes, measuring real connections during real usage hours. The key finding from the 2024 report:
Why does fiber exceed 100%? Providers often over-provision slightly. Why does cable fall short? Shared node capacity during peak hours. A 1 Gbps cable plan realistically delivers 870 Mbps at 8pm. That is still plenty for most uses, but it matters when comparing value.
Full Speed Data Table
| Tech | Plan | Peak DL | Off-peak DL | Upload | Latency |
|---|---|---|---|---|---|
| Fiber | 100 Mbps | 112 Mbps | 115 Mbps | 100 Mbps | 8 ms |
| Fiber | 500 Mbps | 560 Mbps | 575 Mbps | 500 Mbps | 8 ms |
| Fiber | 1 Gbps | 1120 Mbps | 1150 Mbps | 940 Mbps | 8 ms |
| Cable | 300 Mbps | 261 Mbps | 330 Mbps | 20 Mbps | 22 ms |
| Cable | 500 Mbps | 435 Mbps | 535 Mbps | 35 Mbps | 22 ms |
| Cable | 1 Gbps | 870 Mbps | 1050 Mbps | 50 Mbps | 25 ms |
| 5G Home | Typical | 130 Mbps | 220 Mbps | 25 Mbps | 55 ms |
Your Wifi Is Probably the Real Bottleneck
Before blaming your ISP, check your router. Most households cannot use their full plan speed over wifi due to router limitations:
| Wifi Standard | Practical ceiling | Common in |
|---|---|---|
| Wifi 5 (802.11ac) | 300-600 Mbps real-world | Routers 2015-2020 |
| Wifi 6 (802.11ax) | 600-1,200 Mbps real-world | Routers 2019-present |
| Wifi 6E (6 GHz band) | 1,200-2,400 Mbps real-world | Routers 2021-present |
| Wifi 7 (802.11be) | 2,400-5,000 Mbps real-world | High-end routers 2024+ |
To test your true connection speed: connect a laptop directly to your router via ethernet and run a speed test. This isolates ISP speed from wifi. If ethernet is fast but wifi is slow, your router is the bottleneck, not your ISP.
How to Test Your Speed Properly
- 01.Plug your device into the router via ethernet cable (not wifi)
- 02.Close all other tabs and applications that might use bandwidth
- 03.Run the test at least 3 times and note the median
- 04.Test at off-peak (10am weekday) and peak (8pm weekday) for comparison
- 05.Use fast.com (Netflix CDN), speedtest.net (Ookla), and waveform.com for multi-source comparison