What unlimited bandwidth actually means on a mobile line
The word appears on my own listings, so read what follows as coming from somebody with a position to defend. I am going to defend it by explaining exactly what it covers and exactly where it stops.
Unlimited is a billing decision. It says the seller has chosen to charge you by the line rather than by the byte. Everything people assume it says about capacity comes from somewhere else, and there are three separate somewheres.
Start with the arithmetic, because it settles most of the argument
A mobile line moves data at a rate. Take a sustained ten megabits per second, which is unremarkable for a real carrier line doing real work rather than bursting against a nearby speed test server.
Ten megabits per second is roughly 1.25 megabytes per second. Held continuously that is around 108 gigabytes in a day, and around 3.2 terabytes across a thirty day month.
Run the same sum with whatever rate your own line actually holds. The value matters less than the fact that a ceiling exists and you can calculate it in under a minute.
That ceiling is a property of the radio and the calendar. There is no plan or clause behind it, no seller sets it, and no seller can lift it. Which is precisely why the offer is commercially viable: hardly any customer approaches it.
What a real job actually moves
A scraper pulling text pages fetches documents measured in tens of kilobytes. Running continuously for a month at a rate any target would tolerate, that workload does not reach a terabyte. It does not reach a quarter of one.
Account work moves less again. Somebody driving a handful of identities through a browser produces short bursts separated by long gaps, because the work is paced by reading and deciding. The line sits idle for most of the month.
For the majority of what mobile lines get bought for, unlimited describes a limit you would have to work at to touch.
The workloads that get close
Three of them, and they share a property: no idle time.
Video and large media upload. Worse than the file sizes suggest, because a failed upload usually restarts from zero, so a slow uplink on a bad evening bills you twice for the same footage.
Full browser rendering of media heavy pages. One page load pulls images, fonts, video, ad slots and every tracking script. Against the same target, a plain HTTP client moves a fraction of the bytes.
Many workers running around the clock. Idle time is most of what keeps ordinary usage far below the ceiling. Design it out and you find the ceiling.
If your workload looks like one of these, go and do the calculation before you buy, rather than discovering the answer in month two.
The practical ceiling sits under the theoretical one
The three terabyte figure assumes the line holds its rate every hour of the month, which no carrier line does. Throughput sags in the evening when a large number of real subscribers are on the same towers, and it sags again at whatever local hours the cells near the hardware get busy.
So the achievable monthly total is lower than the arithmetic, and the gap moves with the clock rather than staying put. How much lower depends on where the modem physically sits and which carrier it runs on, which is why no honest seller will quote you a figure.
The practical lesson: a workload sized close to the theoretical maximum has been designed to fail every evening.
The carrier plan nobody in the chain controls
Your line sits on a carrier plan somebody bought. That plan has terms. It may carry a fixed allowance, or a large allowance with a threshold past which the carrier reduces speed rather than cutting the session.
No seller sits between you and that decision. When a carrier throttles a subscriber line, the seller learns about it the same way you do, by watching throughput fall.
So an unlimited offer can be entirely sincere and still rest on a plan with its own opinion. The seller’s promise covers what you get charged. The carrier’s threshold covers what the network hands over. A listing collapses both into one word.
Throttling from depletion has a recognisable signature, which I have covered separately: registration stays green, the line answers everything, and throughput sits at a fraction of normal and stays there all day. Worth knowing so you do not spend a week rewriting a scraper that was never the problem.
Unlimited on a pool is a different product
Two things get sold under the same label.
On a dedicated line, unlimited means one customer against one modem on one plan. The ceiling is yours to spend and nobody else is spending it.
On a shared rotating pool, unlimited means there is no per gigabyte charge. What you actually get depends on how many other customers are pulling on the same infrastructure at the same moment. The word is accurate about billing and silent about contention.
Both are legitimate products for different jobs. Comparing an unlimited pool price against an unlimited dedicated line price and concluding the pool is better value compares two different things that happen to share an adjective.
Fair use exists whether it is written or not
Every seller has a fair use position. The only variable is whether you can read it.
A seller who has written one tells you the threshold, or what happens when you cross it, or at minimum that a conversation happens rather than an action. You can weigh that against your work before paying.
A seller who has not written one still has a position. You discover it by triggering it, and the discovery usually arrives as a line that got slower and stayed slower, a renewal that quietly did not process, or a message explaining that your usage sits outside the intended envelope, sent after the fact.
That second experience produces most of the complaints I read from people arriving here from another provider. The anger is almost never about the limit. It is about learning a limit existed at the moment it was enforced.
Three questions to ask before you pay
What happens when I pass whatever threshold sits on the plan behind this line?
A good answer describes a mechanism: we slow you, we bill the excess at this rate, we move you to a larger plan and charge the difference, we contact you and work it out. Any of those tells you what your worst month looks like. Treat a flat assertion that no limit exists anywhere as a warning, because that seller has either not read the plans they buy or has decided the argument is easier to have later.
Is the fair use position written down where I can read it now?
The content matters less than the existence. A seller who points at a paragraph has thought about the case. A seller who tells you not to worry has thought about closing the sale.
How many of your customers have actually hit it?
Nobody asks this and it is the most informative of the three. An operator who measures can answer: it is rare, it happens with one kind of workload, it came up twice last year and here is what we did. That single answer establishes that the threshold is real, that somebody is watching it, and that a process exists. A seller who has never seen anyone reach a limit either has very light customers or is not measuring.
Our own answer to those three
Lines sold here as unlimited carry no per gigabyte charge from us. The plan underneath is a real carrier plan with a real allowance, and when a line runs far past what that plan carries, the cost arrives on our side before it reaches yours. Absorbing that is part of what the margin is for, and the rest of what the margin absorbs is a separate piece.
When it happens, the response is a conversation. Usually the workload changed without anyone noticing, and usually there is a plan or an additional line that fits the new shape. Those conversations have never gone badly when they started early.
What I will not tell you is that a line will hold a terabyte a week indefinitely. The arithmetic at the top of this page puts the ceiling near that, and a line running at that intensity is going to spend real time throttled.
When metered pricing is genuinely the better buy
Unlimited gets treated as the obviously superior model, and for several workloads it is the wrong purchase.
Low volume work pays for what moved and nothing more, while a flat monthly line is capacity bought and never touched. Spiky work, a campaign for ten days then six quiet weeks, matches metered billing in a way a monthly commitment does not. And small amounts of traffic spread across many countries cost less on a metered pool than on a dedicated line sitting idle in each country.
Metered handles one thing badly: work that needs a single address to stay yours. Once a login is attached to the workload, the billing model stops being the interesting question and exclusivity becomes it.
What the word actually claims
Unlimited claims the seller charges by the line. That is the whole of what it says on its own.
The ceiling comes from throughput and hours, and you can work yours out in a minute. The carrier plan underneath carries thresholds no seller controls. And the fair use position exists in every case, so the only question is whether you read it before it applies to you or afterwards.
If you want Singapore mobile lines where that conversation happens before you buy rather than after, that is what I run at singaporemobileproxy.com.
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