How to Diagnose Slow Internet and Wi-Fi at Home or Work

Last reviewed: 13 August 2026.

A slow connection does not always mean you need a faster broadband package. The fault may be the broadband line, weak Wi-Fi, an overloaded local network or one computer. Test those separately before buying a router, extender or more expensive contract.

First, identify the type of problem

• Broadband speed: the connection coming into the property from the internet provider.
• Wi-Fi coverage: the wireless signal between a device and the router or access point.
• Local network capacity: how routers, switches and access points handle several users and devices.
• Device performance: one computer may be slow even when the network is working normally.

These problems can feel identical to the person waiting for a page or video call, but the fixes are different.

Step 1: Check whether every device is affected

Test two devices in the same room. If only one is slow, restart it and check its updates, network driver, VPN, browser extensions and background downloads. Replacing the office router will not fix one unhealthy laptop.

If every device is slow, continue with the network checks.

Step 2: Compare wired and wireless performance

Where possible, connect a laptop directly to the router with an Ethernet cable and run a speed test. Then repeat the test over Wi-Fi in the same area.

• If the wired result is also poor, investigate the broadband service, router or provider.
• If wired performance is good but Wi-Fi is poor, focus on coverage, interference and wireless capacity.
• If both are good but an application is slow, the problem may be that service, its server or the device.

Use the same test device and server for useful comparisons. One result is only a snapshot, so test at more than one time of day.

Step 3: Check router and access-point placement

Wi-Fi weakens through distance, walls, floors and large metal objects. A router hidden in a cabinet, placed on the floor or left at one end of a building will struggle to cover the opposite side.

Move it to an open, central and elevated position where the incoming service permits. Do not place it beside a microwave, large appliance or other equipment that obstructs or interferes with the signal.

Step 4: Look for congestion, not just weak signal

A device can show a strong Wi-Fi signal and still perform badly. Video calls, cloud backups, software updates, cameras and guest devices may be competing for capacity.

At home, pause large downloads and check which devices are active. In an office, note whether the problem appears at busy times, affects one access point or starts when meetings and cloud backups run.

Step 5: Restart safely and check updates

Restart the modem or router using the supplier's instructions, then allow it to reconnect fully. Check whether the manufacturer or internet provider offers a supported firmware update.

On the affected computer, install normal operating-system updates and use the device manufacturer's driver when a wireless-driver fault is suspected. Do not install random "driver updater" utilities.

Step 6: Do not buy an extender before diagnosing coverage

A basic extender can help in a small property, but it may also repeat an already weak signal and create another network name. Mesh systems, wired access points and Ethernet cabling solve different problems.

Choose equipment after checking:

• the size and construction of the property;
• where the broadband enters;
• the number of users and devices;
• whether fixed desks, phones, cameras or printers can use a cable;
• where weak areas actually occur.

Extra checks for an office network

Business Wi-Fi needs more than a fast household router. An office should also consider:

• enough access-point capacity for the number of users;
• channel planning and interference from neighbouring networks;
• separate guest access from business devices;
• stable connections for printers, phones and meeting rooms;
• switch capacity, cabling and power for access points;
• documented administrator access and supported firmware.

If speed is good near the router but poor in meeting rooms or at particular desks, an on-site coverage check is more useful than upgrading the broadband package.

When should you contact the internet provider?

Contact the provider when a wired test at the main router remains materially below the expected service, the connection repeatedly drops, the router shows a line fault or the service fails across every device. Record test times and results so the provider has useful evidence.

When does an engineer need to visit?

An on-site visit is appropriate when coverage varies by room, access points or cabling need checking, office devices repeatedly disconnect, or the correct equipment cannot be chosen from remote tests alone.

Verge Tech provides home Wi-Fi setup and business Wi-Fi and network support across London, Berkshire and Surrey. Book an appointment or send us the test results so we can suggest the right first step.