Every business mobile deal is sold on one number. It is the number on the comparison table, the number in the email, and the number people make the decision on. It is also the number least likely to decide what you actually pay over three years. Here is what to compare instead, in the order it tends to cost you money.
The 30-second version
- The monthly price is the smallest variable. Term length, data behaviour and leaver handling move the real number.
- Ask what happens to the price mid-term, in pounds and pence, before you sign.
- Pool the data rather than buying a bundle per person and getting it wrong in both directions.
- Check who owns the numbers. If they are in an employee's name you do not control them.
- Handset or SIM only is a maths question, not a preference, and the answer changes per user.
- Ask how a leaver is handled before you have one, because you will.
On this page
Term length, and what it really locks in
A longer term buys a lower monthly figure. What it also buys is a fixed view of a business that may not be fixed. Thirty six months is three hiring cycles, two handset generations and, for most small firms, at least one change of direction.
The question worth asking is not "how cheap can we get it" but "what happens if we need to change". Can you add lines mid-term at the same rate? Can you reduce them? Does adding a line restart the clock on that line, or on the account? That last one catches people out: on some arrangements every new starter resets a term you thought was ending.
Shorter terms cost more per month and buy flexibility. Longer terms cost less and buy commitment. Neither is wrong. Picking one without knowing which you are buying is.
What can change mid-contract
This is where the headline price stops being the price. Since January 2025 new contracts cannot carry inflation-linked or percentage-based rises, and any increase has to be stated in pounds and pence at the point of sale.
The catch for businesses is that the rules are not identical to the household ones, and providers retain more flexibility on business agreements. We have covered that properly in what the price rise ban actually means for a business contract, and it is worth five minutes before you sign anything.
The practical test is simple. Can you work out, on the day you sign, what you will pay in month 30? If you can, the contract is doing its job. If the answer involves a formula, you are carrying a risk you have not priced.
How the data actually behaves
Three things decide whether a data allowance is good value, and the headline number is only one of them.
| Ask about | Why it matters |
|---|---|
| Is it pooled? | A shared pot across the account means a heavy month for one person is absorbed by a quiet month for another. Per-line bundles guarantee you overpay on some lines and overrun on others. |
| What happens at the limit? | Does it stop, slow down, or keep going at a charge? Each is defensible. Not knowing which is not. |
| Is unlimited actually unlimited? | Most unlimited tariffs have a fair use position and a view on tethering. Worth reading rather than assuming. |
| What does roaming cost? | Usually a daily charge triggered by the first use of the day. If anyone travels, this is a real line in the budget. |
Our guides on pooled data, what unlimited really means and roaming charges by network go into each properly.
Handset or SIM only
This is arithmetic, not taste, and the answer is usually different for different people in the same business.
A handset contract bundles the phone into the monthly cost over the term. SIM only is cheaper per month and assumes the phone is already there. The thing that decides it is whether the existing handsets have life left in them. A two year old phone in a case on a desk has plenty. The same phone on a building site may not.
The trap is the one nobody mentions at signing: once a handset contract reaches the end of its term, the monthly price often continues unchanged even though the phone is paid for. That is not a price rise, and it costs you exactly like one. We have set out the full comparison in SIM only or handset contract, and the maths behind it.
Who owns the numbers
Worth checking before it matters rather than after.
If a mobile number sits on an account in an employee's own name, with their own direct debit, it is their number. When they leave, it leaves with them, along with every customer who has it saved. Businesses discover this at exactly the wrong moment, usually when a salesperson resigns.
On a proper business account the numbers belong to the business, which means they can be reassigned, diverted or ported as a group. Our posts on who owns a mobile number when an employee leaves and keeping numbers when staff leave cover the detail.
Leavers, starters and the real admin cost
Price comparisons never include the hours. They should.
- How quickly can a new starter be live? Same day with a spare SIM, or a week and a form?
- What happens to a leaver's line? Can it be suspended, reassigned, or does it sit billing until the term ends?
- Who do you ring? A named person who knows the account, or a queue that asks for your account number three times.
- Can you see usage before the bill? Spotting a problem mid-month is worth more than explaining it afterwards.
For a ten line account these are small questions. At fifty lines they are most of the cost of running the fleet, and none of them appear on a comparison table.
Which network, and why the office postcode is the wrong test
Coverage is checked against the office far more often than it is checked against where people actually work. For a team that is out all day, the office is the least relevant location on the list.
We put users on Vodafone, O2 or EE based on where they spend their time, and different people in the same business can sit on different networks for exactly that reason. Where a patch is genuinely mixed, a multi-network SIM uses whichever has usable signal rather than committing the user to one.
Want this done properly rather than quickly?
Send us your current bill and tell us where your people actually work. We will tell you what you are paying for that you do not use, what the increase clauses allow, and what it would look like done well. If your current deal is good, we will say so.