How to Test Your Broadband Speed Properly

How to run a reliable broadband speed test in the UK: wired versus Wi-Fi, what to close first, how to read results and what to do if speeds are low.

A single speed test result tells you very little, yet people complain to their provider based on one number taken on a phone in the bathroom. A proper test separates three things: what your line delivers, what your router delivers and what your Wi-Fi delivers to a particular room.

Know what you are measuring

Download speed is how fast data comes to you, and matters for streaming and browsing.
Upload speed is how fast you send data, which matters for video calls and sharing files.
Latency or ping is the delay, in milliseconds, which affects gaming and calls.

Providers advertise download speeds, often with a typical range. Check your contract or provider information to see what you should expect, including at peak times.

Test the line first, with a cable

To measure what the broadband connection itself provides:

Use a computer connected by Ethernet directly to the router if you can.
Close other programs, downloads, streaming and cloud backups.
Pause other devices or ask others in the house to stop heavy use for a few minutes.
Restart the router if it has been on for weeks.
Run the test three times and note the results.

This is your baseline. If the wired result is close to what you pay for, the line is doing its job.

Then test Wi-Fi, room by room

Repeat the test on a phone or laptop in each important room, noting results next to where the router is. A big gap between wired and Wi-Fi in a given room means the Wi-Fi is the weak link, not the broadband. Our guides on Wi-Fi dead spots and router placement take it from there.

Test at different times

Run tests morning, afternoon and evening. Speeds that fall sharply at peak times can indicate congestion on the provider's network, while consistent low speeds point to a line or equipment issue.

Reading the results

Result	What it likely means
Wired speed close to advertised, Wi-Fi much lower	Wi-Fi coverage problem
Wired speed low at all times	Line, router or provider issue
Fine off-peak, poor evenings	Congestion
Fast download, very slow upload	Normal for many connections, check what is advertised
High speeds but video calls stutter	Latency, Wi-Fi interference or router overload

Things that distort tests

Using a VPN, which adds overhead.
Old devices with slow Wi-Fi chips.
Background updates on any device.
The test server being far away or busy.
A weak router that cannot handle your plan's speed.

If speeds are genuinely low

Check that cables and filters are connected properly where applicable.
Try a different Ethernet cable and port.
Restart the router and try a factory reset if it is misbehaving, noting your settings first.
Test with only one device connected.
Contact your provider with your test results, times and what you tried. Having a record helps.

If the wired speed is fine but your home is unstable, see Wi-Fi keeps dropping.

Do you need faster broadband?

Many households overestimate what they need. Everyday streaming, calls and browsing for a few people run fine on moderate speeds. Problems usually come from the in-home network, not the headline number. A technician can help work out whether upgrading makes sense or whether your money is better spent on a mesh system or wired link, as discussed in mesh Wi-Fi versus extenders.

Getting help

On Compito you can search by postcode, compare ID-verified local providers and send a request with your test results. You receive an offer to accept and pay online and message the provider to agree what will be done. See tech support services.

A worked example: logging results

Suppose you pay for a fibre plan and suspect it is not delivering. You do three wired tests in the evening and three in the morning, noting each. Mornings show results close to what the plan says, evenings are a third lower, and Wi-Fi in the bedroom is lower still. That is useful: the evening dip points to congestion you can raise with your provider, and the bedroom gap points to Wi-Fi coverage you can fix at home. One undifferentiated number could never have told you both.

A simple test log

Time	Where	Connection	Notes
7am	By router	Cable	Nobody else online
8pm	By router	Cable	Streaming in another room
8pm	Bedroom	Wi-Fi	Door closed

A page of six to ten rows is enough to make a conversation with your provider factual, rather than a feeling.

Mistakes that skew results

Running tests on a phone that is also updating apps.
Testing in a room far away and blaming the line.
Comparing a test result to the "up to" figure without allowing for the typical range.
Testing only once, at the worst moment.
Forgetting that older devices may not support the speeds your plan offers.

Edge cases

Flats and shared buildings. Many networks nearby cause interference, so Wi-Fi results change with time. Wired tests help to separate that out.

Mobile and fixed wireless broadband. Speeds vary with signal and time of day. Test in the position where the equipment actually sits and note the signal indicator.

Working from home. Upload speed and latency may matter more to you than download, so record them.

Raising it with your provider

Be calm and factual. Give the dates, times, wired results and what you have already tried. Ask what they see on their side, and ask for any reference number for your complaint. If a fault is confirmed and not fixed, you can usually escalate through their complaints process, and the regulator's rules on complaints give you routes beyond that.

Frequently asked questions

Why is my Wi-Fi speed lower than what I pay for?

Wi-Fi loses speed with distance and obstacles and is shared between devices. A wired test shows the line speed.

How often should I test?

When you notice a problem, after changing equipment and occasionally to check consistency. Constant testing is unnecessary.

Does a speed test use much data?

It can use a few hundred megabytes or more on fast connections, which matters only if you have a data cap or a mobile connection.

Find tech support providers near you

Related guides

Mesh Wi-Fi vs Extenders: Which Is Better for Your Home? — A plain comparison of mesh Wi-Fi systems and plug-in extenders for UK homes: coverage, speed, cost, set-up and which one suits your layout.
Wi-Fi Dead Spots: How to Find and Fix Them — Why some rooms get weak Wi-Fi and how to fix dead spots in a UK home, from router position and channels to mesh, access points and wired options.
Wi-Fi Keeps Dropping? Causes and Fixes at Home — Why Wi-Fi disconnects at random and how to fix it: router restarts, channel interference, device settings, overheating and when the line is at fault.
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Is It Worth Repairing an Old Laptop? A UK Guide — How to decide whether to repair or replace an ageing laptop in the UK, using age, repair cost, performance and support life as practical tests.