What do "up to" and "average" broadband speeds actually mean?
They are defined advertising terms rather than promises, and understanding which one you were given tells you what you can actually hold a provider to.
"Up to" speeds described the theoretical maximum the technology could deliver in ideal conditions. Because copper-based broadband degrades sharply with distance from the cabinet, the great majority of customers never approached the advertised figure — which is why regulators in several countries restricted or banned the practice.
"Average" speeds replaced it in many markets, defined as the speed achieved by a specified proportion of customers — commonly the median, measured at peak evening hours. This is far more honest, and still says nothing about your specific line: half of customers get less than the average by construction.
What your actual speed depends on:
The technology. Full fibre delivers close to its headline figure because light does not degrade over the distances involved. Copper-based connections degrade with line length, which you cannot change.
Contention. Access networks are shared — a street cabinet, a cable segment, a fibre splitter, and the provider's backhaul all carry many customers. Evening congestion is the visible result.
Your own network, where Wi-Fi, an old router or a single slow device is frequently the real limit. Test over Ethernet before blaming the provider.
The far end. A slow download from one server proves nothing about your connection.
What you can hold them to. In several markets a minimum guaranteed speed forms part of the contract, with a right to have the fault remedied within a set period and to exit without penalty if it is not — a genuinely useful right that few people invoke.
How to test properly: wired, not wireless; at several times of day including peak; with nothing else running; using more than one testing service; and using the regulator's or provider's own official test where one exists, since that is the measurement they will accept.
Megabits versus megabytes catches people out — a 100Mbps line downloads at roughly 12MB per second at best.