How many GB per month for your usage?

Eleven point nine gigabytes a month. That is the average consumption of a Belgian mobile customer in 2025, as measured by the regulator. Most plans sold today contain four to five times more, and you pay for them for twenty-four months.

How much data does a Belgian use on average?

11.9 GB a month in 2025, against 3.9 GB five years earlier.

The figure comes from the BIPT, which reports mobile data consumption more than tripling in five years. The same publication notes that by the end of 2025, nearly eight postpaid customers out of ten had more than 10 GB included in their plan, against six out of ten two years earlier.

Put the two figures side by side and the gap is obvious. Consumption is rising, the allowances sold are rising faster, and adding gigabytes has replaced cutting prices. It is a convenient way to enrich an offer without touching the amount billed, and I sold enough plans behind a counter in Namur to know that a customer told "we're giving you 100 GB" almost never asks how many they actually use.

How many GB do you need for your real usage?

Between 5 and 20 GB for the vast majority of lines, and more than that only if you watch video over 4G or 5G every day.

Here are the orders of magnitude, per hour of use, at the applications' default settings.

Resolution is the only variable that really matters. Moving a video app from 1080p to 480p divides consumption by four, with nothing else changed, and on a six-inch screen in a train the quality difference is debatable.

Where do you read your last six months of usage?

In your customer account, under consumption or billing history. Every Belgian operator publishes it month by month.

Take the heaviest month, not the average. That is the one that triggers the overage.

At how many GB does unlimited pay off?

Beyond 260 GB a month. Which is to say, never.

The calculation is a single division. On the Belgian grid surveyed on 24 August 2026, the best price per gigabyte on the market is DIGI Belgium's: 60 GB for €9 a month, or €0.15 per gigabyte. An unlimited plan at €39 with BASE only matches that rate at 260 GB used within the month. With Orange Belgium at €40, the threshold sits at 267 GB. With Proximus at €49.99, it climbs to 333 GB, twenty-eight times the Belgian average.

Take it the other way round, the way that speaks to your wallet. A customer using the Belgian average of 11.9 GB and paying €39 for unlimited data is paying €3.28 per gigabyte. The same usage on the 60 GB plan billed at €9 works out at €0.76 per gigabyte. Over twenty-four months, the gap between the two contracts reaches €720, for a volume the €9 plan already covers five times over. With the most expensive incumbent on the grid, the gap widens to €983.76.

What happens when the monthly allowance runs out?

It depends on the contract, and the three possible behaviours do not cost the same at all.

The third case is the only one that digs into an invoice, and it is the one that kept me busy for three years in the cancellations department of a Belgian virtual operator. A teenager's line tipping into out-of-bundle billing two months running produces an invoice nobody in the house saw coming, because nothing in the contract capped it and the text alert arrives after the threshold is crossed, not before.

Is tethering deducted from the same allowance?

Yes. The data a laptop or a tablet uses through tethering comes out of the line's monthly allowance, exactly as if the phone had used it itself.

This is the item that blows allowances apart, because a computer does not behave like a phone: background system updates, automatic backups, videos that start at full resolution because the screen is bigger. A morning of remote work over tethering uses more than a week of browsing on the phone.

Second point, and it is contractual. Some general terms limit tethering on plans sold as unlimited, and some exclude it. That is neither written on the advert nor said at the counter. It is read in the general terms, in the article dealing with reasonable use.

The four lines to have written down before signing on an allowance

They take five minutes to obtain, and they decide the real cost of your next two years.

• End-of-allowance behaviour, named precisely: throttling, cut-off, or out-of-bundle billing. The three words are not worth the same amount.
• The out-of-bundle rate per megabyte, and the consumption cap the operator agrees to set on the line.
• The numerical threshold of the fair use clause if the plan is sold as unlimited. If it is not disclosed, note that the box remains not published.
• The conditions for moving down an allowance mid-contract. Moving up is always possible; moving down can reopen a commitment period or drop a discount tied to the original plan.

To compare plans on those criteria, the comparison tool puts them side by side and the mobile plan ranking orders them on 24-month cost, handset counted separately. And if the allowance is not your only concern, the article on mobile plans with or without a contract sets out what the contract term changes on the invoice.

One last remark, for readers tempted by a small-allowance plan with no commitment. Mobile Vikings, Scarlet and hey! rent the network of one of the four operators with their own infrastructure on the Belgian market: Proximus, Orange Belgium, Telenet with BASE, and DIGI. The gigabytes you buy therefore travel through the same mast as those of the neighbour paying three times more. What differs is traffic priority when a cell is congested, not the gigabyte itself.

Sources

• BIPT, publication on mobile data consumption in Belgium, consulted on 29 August 2026.
• BIPT, national comparison of mobile tariffs, consulted on 29 August 2026.
• Telecommunications Ombudsman Service, cost-free remedy for consumers in billing disputes, consulted on 29 August 2026.
• Tariff grids published by Belgian operators, surveyed on 24 August 2026. Items operators do not publish are flagged as not published.
• Orders of magnitude per usage: default settings of video and audio streaming applications, at constant resolution.