Your rights

Slow internet: when you can pay less or cancel

Does your connection persistently deliver less than agreed? Then § 57 TKG allows a price reduction or special termination. How to measure correctly and what you need.

Updated: 27 September 2026 Reading time: 7 min Tim Jungeblut Editorial methodology

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What the contract says counts, not the advertising
The Federal Network Agency’s measurement protocol
When a discrepancy counts as significant

Since the reform of the Telecommunications Act (TKG), persistently low bandwidth is no longer just bad luck; it is a defect. What matters is that you prove the discrepancy using the measurement tool of the Federal Network Agency (Bundesnetzagentur), the desktop app from breitbandmessung.de. Browser speed tests are not enough.

What the contract says counts, not the advertising

The three figures in the product information sheet (Produktinformationsblatt) are what matter: the minimum, the normally available and the maximum speed. An advertised “up to” is not a guaranteed figure; the comparison is always made against these three contractual values.

Under § 57(4) TKG, a significant, continuous or regularly recurring discrepancy entitles you to reduce the fee or to terminate the contract early.

Find your product information sheet
Note the minimum, normal and maximum speeds
Look at download and upload separately

The Federal Network Agency’s measurement protocol

The evidence is a measurement with the Federal Network Agency’s measurement tool, the desktop app from breitbandmessung.de. You need 30 measurements on three different calendar days: ten per day, with at least five minutes between any two measurements and at least three hours between the fifth and sixth measurement of a day.

Measure over a LAN cable connected directly to the router and stop any other downloads or streams. Wi-Fi measurements are not suitable for this evidence, because they measure the wireless link as well as the connection itself.

Desktop app rather than a browser speed test
30 measurements on three calendar days
Measure over a LAN cable, not Wi-Fi
Keep the measurement report as evidence

When a discrepancy counts as significant

It is enough for one of three criteria to be met: the maximum speed is not reached at 90 per cent at least once on each of at least two of the three measurement days; or the normally available speed is not reached in 90 per cent of the measurements; or the speed falls below the minimum at least once on each of at least two of the three measurement days.

The reduction is proportionate to the discrepancy found. The law does not set a fixed rate; how much it comes to in a particular case depends on the measurement results and the contract. If you disagree with your provider about the amount, the consumer advice centre (Verbraucherzentrale) or the Federal Network Agency’s conciliation procedure (Schlichtungsverfahren) can help.

Frequently asked questions

Is an ordinary browser speed test enough as evidence?

No. For a price reduction or special termination under § 57 TKG, you need to measure using the procedure provided by the Federal Network Agency (Bundesnetzagentur), i.e. the desktop app of its broadband measurement service (Breitbandmessung). Browser speed tests are useful as a guide, but they are not suitable as evidence for your provider.

How much can I reduce the price by?

The reduction is proportionate to the gap between the speed agreed in the contract and the speed you actually get. There is no percentage set by law. Keep a record of the measurement results and tell your provider in writing what you are basing the reduction on.

Can I cancel straight away if the internet is too slow?

An extraordinary right to terminate exists under the same conditions as the price reduction: a significant, continuous or regularly recurring discrepancy, proven using the official measurement procedure. Without that evidence, the normal notice periods apply.

Selected sources

Note: This article is general information and not legal advice. It does not replace an assessment of your individual case by a lawyer or a consumer advice centre. No guarantee of accuracy; the law and case law may change.