Is Your Line Slow Enough to Cut the Bill?
German law lets you reduce a broadband charge, or terminate without notice, when the measured speed misses the contract badly enough. Three official tests decide it and any one of them is enough. Put the three speeds from your Vertragsinformationsblatt and the fastest and slowest reading from each of your three measurement days in, and the chart shows exactly which rule you are already meeting.
The three tests come from the Bundesnetzagentur Allgemeinverfuegung Nr. 99/2021 of 8 December 2021 and from the measurement rules published at breitbandmessung.de, checked on 23 September 2026. The reduction and termination rights are section 57 paragraph 4 of the Telekommunikationsgesetz. The law sets the proportion of the reduction, not the arithmetic, so the euro figures are the band an argument sits in.
Only 45.9 per cent of measured German households reach the full download speed their contract promises, and almost nobody claims anything for it. The right has been there since December 2021: when the measured speed misses the contract in one of three specific ways, you can reduce what you pay or walk out without notice. The catch is that the proof has to come from the Bundesnetzagentur own Desktop-App, ten measurements a day on three different calendar days, and the three tests are precise. This tool takes the three speeds off your contract summary and the best and worst reading from each measurement day, plots them against the three legal thresholds, and tells you which rule you are meeting and roughly what it is worth on your monthly charge.
Where the three speeds come from
Your provider had to give you a Vertragsinformationsblatt before you signed, and it carries three separate download figures: a maximum, a normally available speed and a minimum. Only the maximum is ever advertised. Every one of the three legal tests is measured against one of those numbers, so without the sheet there is no claim to make. It is in the confirmation email from the day you signed, or in your account area under contract documents.
What counts as proof
Only the measurement report from the Bundesnetzagentur Breitbandmessung Desktop-App. The campaign needs ten measurements a day on three different calendar days, at least one clear calendar day between measurement days, no more than fourteen days end to end, at least three hours between the fifth and sixth measurement of a day and at least five minutes between the others. Run it on a computer plugged into the router by cable with nothing else using the line.
What the euro figures mean
Section 57 says the agreed charge is cut in the proportion by which the actual performance deviates from the agreed performance, and leaves the arithmetic open. So the two numbers here are a band, not a settled amount: one measured against the maximum speed, one against the normally available speed. Once the breach is proven, the right to keep paying less runs until the provider proves it is delivering properly.
What it cannot tell you
It cannot run the measurement for you, and a browser speed test will not substitute. It also cannot tell you what your provider will agree to, because the reduction is negotiated. What it can do is tell you before you start writing whether your own readings already meet one of the three tests, which is the only part a provider cannot argue with.