- Broadband speed is shaped by both in-home factors and external factors on the line and network.
- WiFi conditions, router placement and device age often limit speed more than the broadband line itself.
- On part-fibre lines, distance from the street cabinet reduces the achievable speed.
- Network contention can lower speeds at peak times, which Ofcom tracks in Connected Nations reporting.
- A wired speed test from the router isolates the line from WiFi and gives the truest measure of speed.
Broadband speed depends on in-home factors such as WiFi, router placement and device age, and external factors such as cabinet distance, congestion and line quality. A wired test isolates the line itself.
Last reviewed: June 2026
Two sides of the speed question
When a connection feels slow, the cause can lie inside the home or out on the network, and telling the two apart is the key to fixing it. In-home factors include the router, where it sits, the WiFi conditions, the age of the devices and how many are connected. External factors include the technology of the line, the distance from the street cabinet on part-fibre connections, the quality of the line, and congestion on the shared network at peak times. A slow experience often comes from a combination of these rather than a single cause.
The most useful first step is to separate the line from the home network. A wired speed test, taken from a device connected to the router by an Ethernet cable, removes WiFi as a variable and shows what the line is delivering. Comparing that with a WiFi test reveals how much the home network is contributing to any slowdown.
Router placement and WiFi
WiFi is one of the most common reasons a fast line feels slow at a device. The wireless signal weakens with distance and is absorbed by walls, floors and large objects, so a device far from the router, or separated by thick walls, may receive only a fraction of the line speed. A router tucked inside a cupboard or behind a television performs worse than one placed in the open. Interference from neighbouring networks and household electronics can also reduce WiFi performance, particularly on the crowded 2.4 GHz band.
Because WiFi is so influential, improving placement and reducing interference often does more for real-world speed than upgrading the package. Moving the router to a central, open position, and using the appropriate frequency band for the device and distance, can recover speed that poor WiFi conditions had lost.
| Factor | Where it sits | Typical impact |
|---|---|---|
| WiFi and router placement | In the home | Often large at the device |
| Device age and capability | In the home | Caps the speed a device can reach |
| Connected device count | In the home | Divides speed when many are active |
| Cabinet distance (part fibre) | On the line | Lower speed further from cabinet |
| Network congestion | On the network | Peak-time slowdown |
| Line quality or fault | On the line | Reduced or unstable speed |
Device age and capability
The device being used sets a ceiling on the speed it can achieve. An older laptop, phone or tablet may have a WiFi adapter that cannot reach modern speeds, so even on a gigabit line it will record far less. The same applies to older network equipment, such as an ageing router or a low-specification network card. Where one device is slow but others are fast, the device itself is often the limiting factor rather than the broadband.
Number of connected devices
Every connected device shares the connection and the home network. A household with many devices streaming, downloading, backing up and updating at once divides the available speed among them, which can make any single device feel slower. Background activity, such as automatic updates and cloud backups, can consume bandwidth without anyone noticing. Managing when heavy tasks run, and being aware of how many devices are active, helps keep the connection responsive for whatever matters most at the time.
Distance from the cabinet
On part-fibre connections such as fibre to the cabinet, the copper run from the street cabinet to the home reduces the achievable speed with distance. A property close to its cabinet can reach the top tier, while one further away sees less. This is a property of the line rather than the home network, and it is reflected in the personalised speed estimate a provider gives at the point of sale. Full fibre removes this distance penalty, because there is no copper section.
Network congestion
Because consumer broadband is shared, speeds can dip at peak times when many users are online at once, typically in the early evening. The size of this dip depends on how well the provider has sized its network against demand. Ofcom tracks peak-time speeds in its Connected Nations reporting. A connection that is fast late at night but slower in the evening is showing the effect of congestion, which is a network factor rather than a problem inside the home.
Line quality and faults
The physical quality of the line also matters, especially on copper-based connections. Old or damaged wiring, poor joints, water ingress and electrical interference can all reduce speed or cause instability. Internal wiring and extension sockets can have the same effect. Where a line underperforms its estimate and the home setup is sound, a fault on the line may be responsible, which the provider can investigate and, where it lies in the network, arrange to repair.
Diagnosing a slow connection
Bringing these factors together gives a simple diagnostic approach. Start with a wired test from the router to see the line speed. If the wired speed is good but WiFi is poor, the home network is the issue, so look at router placement, interference, the frequency band and the device. If the wired speed itself is low, look at the line: the technology, the cabinet distance, the time of day for congestion, and the possibility of a fault. Working through the chain in this order usually identifies the real cause rather than guessing.
What actually helps
The most effective improvements depend on which factor is limiting speed. Better router placement, reducing interference and using wired connections for important devices help where the home network is the bottleneck. Upgrading an old device helps where that device is the limit. Moving to full fibre removes the cabinet-distance penalty and adds headroom against congestion. Upgrading the package only helps if the line, not the home setup, is the constraint. Matching the fix to the cause is what makes the difference, rather than assuming a faster package will solve every kind of slowdown.
Frequently Asked Questions
Why is my broadband slow in the evenings?
An evening slowdown usually reflects network contention, where shared capacity is divided among many users at peak times. The size of the dip depends on how well the provider has sized its network. A connection that is fast late at night but slower in the evening is showing congestion rather than a fault inside the home.
Does more connected devices slow broadband?
Yes. Every device shares the connection, so many devices streaming, downloading, backing up and updating at once divide the available speed. Background activity such as automatic updates can use bandwidth unnoticed. Managing when heavy tasks run helps keep the connection responsive for what matters most.
Does the distance from my cabinet matter?
On part-fibre connections such as fibre to the cabinet, the copper run from the street cabinet reduces the achievable speed with distance, so a property further from its cabinet sees less. Full fibre removes this penalty because there is no copper section. The effect is reflected in the personalised speed estimate.
How does my router affect broadband speed?
The router shares the line over WiFi and wired ports, so its placement and capability strongly affect real-world speed. A router in a cupboard or behind a television performs worse than one in the open, and an older router may not reach modern speeds. Better placement often helps more than a package upgrade.
Will a new router make my broadband faster?
A new router helps where the existing one is the bottleneck, for example if it is old, poorly placed or cannot reach modern WiFi speeds. It will not raise the speed of the line itself. If a wired test shows the line is slow, the cause lies on the line or network rather than the router.
How do I tell if the problem is my WiFi or my line?
Run a wired speed test from a device connected to the router by an Ethernet cable, then compare it with a WiFi test. If the wired speed is good but WiFi is poor, the home network is the issue. If the wired speed itself is low, the cause lies on the line or network.
