Buried in the email your provider sent when you signed up is the most useful number in your whole contract: your minimum guaranteed speed. It is not a marketing figure or an average. It is a personalised promise, made to your specific address, and if your provider cannot keep it, you have the right to walk away from your contract without paying an exit fee. Most people never use that right because they never test properly, or they test once, shrug, and accept a connection that underperforms for two years. This page explains how the guarantee works, how to build the evidence that activates it, and what happens on day 30. A good first step is to run a broadband speed test now and write the result down, because the record you build from today is what turns a slow line into a contractual case.
What the minimum guaranteed speed actually is
When you buy broadband, providers signed up to Ofcom’s Broadband Speeds Code of Practice must give you, before you commit, a realistic estimate of the speeds your line should achieve at peak times, and a minimum guaranteed speed: a download figure below which your service should not fall. The code’s signatories include BT, EE, NOW Broadband, Plusnet, Sky, TalkTalk, Utility Warehouse, Virgin Media and Zen Internet, so most households are covered.
The guarantee is personalised. Two houses on the same street can have different minimums, because it depends on the length and condition of the line to your home. It is also deliberately a floor, not a target: it sits below the estimated range, representing the worst acceptable performance rather than the typical one. Advertised “average” speeds, by contrast, are what at least half of a provider’s customers achieve at peak time. Comparing your speed test result against the advertised average tells you very little. Comparing it against your own minimum guarantee tells you whether your provider is in breach of a promise.
You will find your figure in your order confirmation, your contract summary, or your provider’s app and account pages. If you cannot find it, ask; the provider is required to tell you. Write it somewhere you will not lose it, alongside the date your contract started.
Measure like you mean it: the rules of a fair test
Providers are entitled to check whether the problem is on their network or inside your home, and honestly, they are right to: a large share of “slow broadband” is slow Wi-Fi. So measure in a way that removes the argument.
- Test wired. Connect a laptop or computer to the router with an Ethernet cable for your evidence tests. Wi-Fi results vary with walls, distance and neighbours; cable results measure the line itself. If you cannot wire up, sit in the same room as the router with a clear line of sight and say so in your notes.
- Test at peak time. Guarantees are framed around peak performance, roughly 8pm to 10pm. Test then, not at 6am when the network is empty. A line that hits its estimate at breakfast and collapses every evening is exactly the failure the code exists for.
- Test with the house quiet. Pause downloads, cloud backups, games updates and other streams, and disconnect or idle other devices. A speed test shared with a teenager’s game download measures your household, not your line.
- Test on several days. One bad evening proves nothing; a week of sub-guarantee results at peak time is a case. Log the date, time, result and how you tested. A simple notebook or a notes app is fine.
- Restart the router once, and note it. If a restart fixes things permanently, wonderful. If speeds sag again within days, that pattern is itself evidence of a line or equipment problem.
For a longer, hands-off record, our internet speed monitor tracks your connection over time, and the internet stability test picks up the dropouts and wobbles that a single speed test misses. Together they give you a timeline rather than a snapshot, which is far harder for a provider to wave away.
Starting the clock: report it as a fault
The 30-day countdown does not start when your speeds drop. It starts when you report the problem to your provider. Report it through a channel that leaves a record (app, web chat, email, or a phone call where you take the agent’s name and a reference), and say the specific words: your speed is below your minimum guaranteed speed, and you want it logged as a speed fault under the speeds code. Vague complaints about “slow internet” can drift; a named, referenced fault cannot.
From there, the provider must take reasonable steps to fix the problem. Expect a sequence: checks on your set-up, line tests from their end, possibly a replacement router, possibly an engineer visit. Cooperate with all of it, and keep your own log running in parallel. If they ask you to test again, test, and record their result alongside yours. If your provider wants to verify your speed, they can use their own checker or lend equipment; what they cannot do is stall indefinitely. There are narrow exceptions where the clock can be extended, such as you cancelling engineer visits or streetworks permissions delaying an external repair, but the default is 30 calendar days from your report.
Day 31: the right to exit
If, 30 days after you reported it, your download speed is still below your minimum guaranteed speed, you must be offered the right to leave your contract without any early termination charge. That right reaches beyond the broadband itself: services in the same bundle that depend on the connection, such as a landline or TV package bought with it, can be cancelled penalty-free too, so you are not left paying for a TV bundle stranded without broadband. It does not extend to genuinely separate products, like an unrelated mobile contract.
You do not have to leave. Some people use the right as leverage: a provider that cannot fix your line may offer a discount, a move to a different technology (from part fibre to full fibre, for example), or a release to a network that can serve you better. But the right is yours, time-limited once offered, so decide promptly. If you do leave, switch using One Touch Switch so the new service starts as the old one stops, and your old provider will confirm the exit fee position (zero, in this case) before the switch completes.
If your provider disputes your evidence, refuses to log the fault, or simply runs the clock without acting, treat it as a formal complaint. Put the timeline in writing: guarantee figure, test results, report date, their responses. Providers signed up to the code know exactly what a well-kept log means, and complaints teams resolve these cases far more readily than front-line agents can.
Full fibre, part fibre and a note on upload speeds
Two honest complications. First, the guarantee focuses on download speed. Upload speed matters enormously for video calls and working from home, but the code’s exit right is built around the download figure, so if your problem is purely upload, expect to argue it as a general service complaint rather than a code breach. Second, the technology matters: on part fibre (FTTC) lines, the guaranteed figure relates to what your individual line can carry, and a below-guarantee result usually points to a line fault an engineer can address. On full fibre, speeds well below the guarantee more often indicate an in-home or equipment issue, which is why the wired testing discipline above matters so much before you report.
Plusnet’s summary of the Ofcom speed code shows how a signatory provider presents these commitments, and Choose’s guide to minimum guaranteed download speeds works through the mechanics from a consumer angle, including the difference between estimates and guarantees. Reading your own provider’s version of the code page is worthwhile; it is the document you will be quoting.
Frequently asked questions
Where do I find my minimum guaranteed speed?
In your order confirmation, contract summary, or account pages/app. It is a personalised download figure for your address, different from the advertised average speed of the package. If you cannot find it, your provider must tell you; ask them to confirm it in writing.
My speed is below the estimate but above the minimum. Can I leave?
Not under the speeds code: the exit right is triggered by falling below the minimum guarantee, not the estimate. You should still report it, because a persistent shortfall may indicate a fault, and your evidence log remains useful in a general complaint. If you are out of contract, of course, you can leave anyway.
Does one slow evening count?
No. The code is about a persistent failure to reach the minimum, and providers get 30 days from your report to investigate and fix it. That is why a week or two of logged peak-time results, tested over a cable, is the foundation of a successful case.
What if the problem turns out to be my Wi-Fi?
Then it is genuinely not a code issue, and your wired tests will have shown it: if the line hits its guarantee on a cable but not over Wi-Fi, the fix is router placement, a mesh system or a wired connection for the devices that matter. Our Wi-Fi speed test page helps separate line speed from wireless speed.
Does the right to exit cover my TV package too?
Yes, where the TV or phone service was bought as part of the same bundle and depends on the broadband. You cannot be left trapped paying for a bundled service that was sold to work with the connection you are releasing. Separate, independent contracts are not covered.
Your guarantee is only useful if you use it
The minimum guaranteed speed is a rare thing in consumer contracts: a measurable promise with a defined consequence. But it only activates for people who test properly and report promptly. Find your figure, spend a week logging peak-time wired results with the tools on the SpeedTestUK homepage, and if the numbers fall short, make the call and start the clock. Thirty days later you will either have the broadband you were promised, or the freedom to go and find it elsewhere.
