Local Network
Local Network Speed: Measure Your LAN Throughput
The Local Network Speed test characterizes your home or office LAN throughput independent of your internet connection. It tells you whether your switches, cables, and network adapters are delivering the speed your gear advertises, which determines how fast file transfers and local services actually feel.
What It Measures
This tool measures local network throughput in megabits and megabytes per second, plus latency and packet loss within your LAN. It separates internal performance from internet performance so you can isolate which side has the problem.
How It Works
- Detects your reported link speed (1 Gbps, 2.5 Gbps, 10 Gbps) where available
- Probes local network endpoints accessible from your browser
- Compares observed throughput against expected link rate
- Reports efficiency percentage and identifies likely bottlenecks
Why It Matters
Slow file transfers between your laptop and NAS, choppy local video streaming from a Plex server, or laggy response from a local game server all point to LAN problems, not internet problems. Diagnosing them requires measuring local throughput specifically, separate from any internet speed test.
Understanding Your Results
On a healthy gigabit LAN, expect 900 Mbps or higher of usable throughput. On 100 Mbps links, expect 90 Mbps or higher. On 2.5 Gbps links, expect 2.3 Gbps or higher. Local latency should be under 1ms for wired connections and under 5ms for WiFi. Any packet loss on a wired LAN indicates a hardware problem.
Frequently Asked Questions
Why does my LAN feel slow even with gigabit gear?
Common reasons include one bad cable in the path that forces fallback to 100 Mbps, an old switch with limited backplane bandwidth, a NIC stuck in half duplex mode, or a CPU bottleneck on the file server. Identifying the slowest link in the chain is essential, since LAN speed is limited by its weakest segment.
Can my internet plan affect LAN speed?
No. Local network speed is independent of your internet plan. Your gigabit LAN can transfer files at full speed even on a 25 Mbps internet connection because LAN traffic never crosses your modem. This is why home NAS, Plex servers, and local backups can be fast even when your internet is slow.
What is the difference between LAN and WAN?
LAN (Local Area Network) is your internal network including switches, cables, WiFi, and devices in your home or office. WAN (Wide Area Network) is your connection to the wider internet through your ISP. Local Network Speed tests LAN performance only; tools like Speed Test measure WAN performance.
Should I use ethernet or WiFi for best LAN speed?
Wired Ethernet is faster and more consistent than WiFi for local network performance. Gigabit Ethernet delivers a sustained 940 Mbps with low latency. Even WiFi 6 typically delivers half that speed with higher jitter. For NAS, file server, and local game server traffic, prefer Ethernet whenever possible.
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