Real vs Advertised Internet Speed: What to Expect

Your plan says 1 Gbps and your test shows 280? That is not necessarily a scam. Advertised speed is a theoretical maximum; in Belgium, real speed commonly lands 20-30 % below it, and up to 50 % lower over Wi-Fi. What counts is the "normally available" speed written into your contract: that is the figure that protects you.

Advertised speed, or theoretical maximum speed, is what your line can reach under perfect conditions: cable plugged in, new router, empty network. Real speed is what you measure on a Tuesday at 9pm, over Wi-Fi, while the whole household streams a series. In short: the two numbers do not measure the same thing, and only one of them is written into your contract.

Why is my real speed lower than the advertised speed?

Because the advertising figure is a ceiling, not a promise. Between the test server and your screen, every link takes its cut: Wi-Fi, the age of your router, the length of the line, the load on the network in your street. Real speeds often run 20-30 % below the advertised plan.

Three causes dominate in Belgium. Wi-Fi first: a signal crossing a load-bearing wall or a floor easily loses half its speed. Technology next: the coaxial cable used by Telenet and VOO is shared between neighbours on its final segment, so it slows at peak hours, often between 8pm and 11pm; VDSL, meanwhile, weakens with distance from the telephone exchange. Hardware last: an old router or a dated Wi-Fi card throttles the line long before the provider does.

The figure that puts things back in perspective: average download speed measured in Belgium sits between 100 and 120 Mbps, with upload around 20 Mbps (Ookla). In other words, the national average is nowhere near the gigabits on the billboards — and yet most households never complain, because 100 Mbps covers almost everything.

What gap between advertised and measured speed is normal?

Over Ethernet, a 10-20 % shortfall is normal. Over Wi-Fi, expect a 30-50 % loss. Beyond those margins, it is no longer physics: it is a problem, either in your home or at your provider.

The table below gives the orders of magnitude to keep in mind before you pick up the phone. It does not replace your contract; it tells you whether your disappointment is justified or whether you are simply measuring badly.

In practice: if you pay for a 1 Gbps plan and your PC measures 800 Mbps over Ethernet, all is well. If it measures 300 Mbps over Wi-Fi from the back bedroom, look at your Wi-Fi, not your provider. But if it tops out at 120 Mbps over Ethernet, at any hour, several days running, you have a case.

The three speeds your contract must state

This is the point comparison sites almost always skip. BIPT requires fixed internet providers to state, in the contract and on their website, three distinct speeds — not just the "up to" of the advertising.

The minimum speed is the value below which the provider commits never to fall, outside a service interruption. The normally available speed is what you should get most of the time, meaning at least 95 % of the time: this is the real reference. The maximum speed is the theoretical ceiling, the one on the billboards and almost never on your screen.

How do I measure my speed properly?

Plug a computer straight into the router with an Ethernet cable, shut down whatever eats bandwidth, then run several tests at different hours — including one in the middle of the evening. Record the date, the time and the result each time.

BIPT is explicit here: it is in your interest to gather the most precise possible evidence of a failing speed. An isolated test, on a Tuesday at 10am, over Wi-Fi, from an old laptop, proves absolutely nothing — and your provider knows it. A log of ten measurements spread over two weeks, over Ethernet, with three evening runs at 9pm, changes the conversation entirely.

Wi-Fi or Ethernet: which one distorts the test?

Wi-Fi, without hesitation. It is the weak link in almost every Belgian connection, and on its own it can wipe out half the advertised speed. A Wi-Fi test measures your Wi-Fi, not your subscription.

The reflex that solves half of all "outages": move closer to the router, or better, plug in a cable. Plenty of households who believe they are being short-changed discover they are paying for a speed their six-year-old router never knew how to carry as far as the living room.

What if the speed stays too slow?

Three steps, in order. First the provider, evidence in hand, in writing. Then the Telecommunications Ombudsman, free of charge. Finally the exit: compensation or termination.

BIPT puts it plainly: where there is a significant, constant or regular difference between real speeds and those stated in the contract, the provider must take action to reach the promised level. If those actions resolve nothing, you are entitled to contractual remedies — compensation for the damage and/or termination of the contract. The Telecommunications Ombudsman, for its part, provides free mediation towards an amicable settlement.

Can I terminate for free over insufficient speed?

Yes, but only at the end of the road. Termination is indeed among the possible remedies when the provider fails to bring the speed back to the contractual level (BIPT). It is not a right you trigger by snapping your fingers after one bad speed test.

What makes the difference is the quality of your file: repeated measurements, over Ethernet, compared against the normally available speed in your contract. Without that, the provider will point you back to your Wi-Fi — and will often be right.

Should you pay more for a higher speed?

Usually not. Going from 500 Mbps to 1 Gbps will change nothing about your Netflix, your video calls or your online gaming. The extra speed only pays off if several heavy users share the line or if you regularly download very large files.

Independent Ookla measurements (Q3-Q4 2025, relayed by RTBF) put Proximus top on overall speed with 301.8 points, ahead of VOO (174.7) and Telenet (161.2). Those scores compare networks, not your living room: on fixed lines Telenet and VOO remain solid while Proximus catches up thanks to fibre. At your address, the technology actually connected to your door will always weigh more than a national ranking.

Is 1 Gbps of any use at home?

Rarely, in classic household use. 4K streaming needs around 25 Mbps per stream: even a family of four streaming 4K at once stays under 100 Mbps. A gigabit mainly earns its keep for fast downloads (a 120 GB game), for a household of heavy users, or for a streamer who needs upload.

Before upgrading, check what is actually limiting you. A recent router, an Ethernet cable and a well-placed box often return more Mbps than a bigger plan — and they cost you once, not every month. And if you want to know what your line can really carry, the address angle stays decisive: our guide on cable or VDSL: why your address changes everything explains why two neighbours do not get the same speed.

To go further, compare the best internet provider, read our guide to choosing an internet provider, or see what latency changes for gaming. The rules on contractual speeds and complaints are detailed on the BIPT website.