Why a 1 Gbps plan tests below 1,000 Mbps

You pay for a 1 Gbps internet plan, run a speed test, and see 920 Mbps instead of 1,000. That result can be normal, especially over a wired connection. A lower number can also point to a Wi-Fi limit, a slow cable or port, or another device using the connection.

Use the Speed Test to measure your connection, then compare a wired result with Wi-Fi if possible. The steps below help you tell normal overhead from a setup problem.

Test your connection consistently

1. Open the Speed Test on the computer you want to check and run a test. Note the download speed, upload speed, ping, and jitter.
2. If possible, connect the computer to the router with Ethernet. Connect directly to the router rather than through a Wi-Fi extender, powerline adapter, or dock, if you can. Pause downloads, video streams, and cloud backups on other devices.
3. Run the test two or three times from the same location. A single run can vary because other internet traffic and the test route change over time.
4. Compare the wired result with a Wi-Fi result, or test another computer on the same wired connection. Keep the test conditions as similar as you can.

A speed test sends and receives test data with a server to measure throughput. Results can vary with the route to that server, so focus on the pattern across repeated runs rather than one exact number.

What the result means

About 900 to 950 Mbps over Ethernet

This is often a healthy result for a gigabit connection. The plan's 1 Gbps rate describes the maximum connection rate, while protocol overhead uses some of that capacity to carry addressing and control information. The test measures useful data, so it usually reports less than the full link rate. Your router, computer, and provider can also affect the final number.

Also check the units: 1 Gbps is 1,000 megabits per second, or 125 megabytes per second before overhead. A download showing about 115 megabytes per second is roughly 920 Mbps, not 115 Mbps.

About 90 to 100 Mbps, or a result near 100

This often means one part of the wired connection has negotiated a 100 Mbps link instead of a 1 Gbps link. The cable, router port, computer port, adapter, or dock may be limited or faulty. Check the connection speed before assuming your internet plan is the problem.

Much lower on Wi-Fi

A Wi-Fi speed test measures the whole wireless path, not just the plan. Distance, walls, interference, the router's capabilities, and the computer's Wi-Fi hardware can all reduce throughput. A wired test is a better way to check whether the internet service itself can approach gigabit speeds.

Results change a lot between runs

Short-term variation can come from other activity on your home network, wireless interference, or a busy route to the test server. If wired results are consistently lower at different times, while other devices are idle, investigate the router, computer, and provider connection.

How to improve a low result

1. Use a direct Ethernet connection. Test with a cable from the computer to a gigabit-capable router port. Extenders, switches, docks, and powerline adapters can introduce slower links, so temporarily bypass them to narrow down the cause.
2. Check the negotiated link speed. In Windows 11, open Settings › Network & internet › Ethernet and look for Link speed (Receive/Transmit). On a Mac, open System Settings › Network › Ethernet to check the connection. For adapter details, open Apple menu › System Settings › General › About › System Report › Network › Ethernet, where the reported speed may be listed. A 100 Mbps link cannot deliver a 1 Gbps test result.
3. Try another cable and router port. Use a known-good Cat 5e or Cat 6 cable and a router port rated for gigabit speeds. Check that each connector is fully seated. If the link speed changes after swapping either part, you have found a likely bottleneck.
4. Check the computer's adapter or dock. Some USB adapters and older docks have 100 Mbps Ethernet, even when the router and plan support gigabit. Try the computer's built-in Ethernet port or a gigabit-capable adapter, if available.
5. Reduce other network activity. Pause large downloads, backups, and streaming on other devices, then repeat the test. For Wi-Fi, move near the router and test with a clear path between the devices. On Windows 11, check Settings › Network & internet › Wi-Fi; on a Mac, check System Settings › Wi-Fi to confirm which network you joined.
6. Restart the router and retest. Restart it once, wait for the connection to return, and test again. If several direct-wired tests remain far below what your plan should provide, ask your internet provider to check the service profile and the connection to your home.

Why 1,000 Mbps is not always the test result

The number in your plan is a rate, not a promise that every application will receive exactly that much usable data in every test. Network protocols add information to the data being sent, and equipment processes that information. A speed test also depends on the browser, computer workload, router, and test server.

A one-gigabit Ethernet port is not the same as a guaranteed 1,000 Mbps of measured internet throughput. Around 900 to 950 Mbps on a suitable wired setup is commonly close to the practical limit. If you need more than that, the router, computer connection, and service plan all need to support a faster-than-gigabit link.

Use repeated wired tests to judge a gigabit plan, and treat a small gap below 1,000 Mbps as normal rather than a fault.