Many business phone providers sell their plans with unlimited calls or with a bundle of a few hundred minutes a month. That feels safe, because you know in advance what you will pay and never get a surprise. Almost every set of terms, though, contains a fair usage policy, and that decides what unlimited means in practice.

In this article we explain how a fair usage policy works, how much a business line carries on average and why paying per minute works out better for most businesses. It follows on from our article on business phone systems per user or per minute, which explains why telephony fits poorly with per-user pricing.

How much does a business line actually carry?

Most people overestimate how much each line is used. According to Ofcom, UK businesses made 1.54 billion call minutes across 4.56 million business lines in the fourth quarter of 2025. That works out at about 113 minutes per line per month.

A bundle of 500 minutes, sold to a line that uses 113, means you pay for 387 minutes every month that nobody calls. With unlimited calls the gap is even wider, because you are paying for capacity that in practice is barely touched.

What a fair usage policy means in practice

A fair usage policy is the rule a provider uses to set out what counts as normal use. Anyone who goes above it can face extra per-minute charges, restricted use or a conversation about a different plan. Unlimited calls are therefore unlimited within a limit the provider sets itself.

Pay particular attention to what counts. On some plans, incoming calls also count towards the fair usage limit, and forwarding, automated dialling or call-centre use are often excluded. A business that is mostly called by customers can therefore reach the limit sooner than it expects.

Why a bundle averages out the risk

A provider selling unlimited calls works out a price based on the average use of all its customers. Businesses that call little therefore pay towards the businesses that call a lot, and the fair usage policy protects the provider against the customers who push the average too high.

For the provider that is a tidy model. For you it means that with average or light use you almost always pay more than your real usage costs, while with heavy use you still run into a limit.

How paying per minute works

When you pay per minute, you pay exactly for the calls that took place. With CallFactory, a call delivered over the internet to a softphone or desk phone costs 5p a minute, and calls you place to the UK, Europe and the United States are the same rate. Delivery to a mobile or landline on premium routes costs 10p a minute, because that leg runs over the fixed and mobile phone networks.

So no fair usage policy is needed, because there is no limit to protect anyone from. You always have enough capacity, calls arrive over good routes or over the internet, and the per-minute price also covers the lines and the platform: routing, opening hours, menus, queues, voicemail and the dashboard. Greetings, queues and voicemail do not count as a separate call either.

A worked example

Take a team of four people sharing one business number. With us that falls under Team 8, which costs £43 a month for up to eight people. If the team together makes the average 113 minutes, that adds £5.65 to £11.30 in minutes, depending on how many calls end up on a mobile.

If the same team makes 250 minutes a month, you pay £12.50 to £25 in minutes, so £55.50 to £68 in total. On an unlimited plan at £15 per user, the same four people cost £60 whether they make 113 or 250 minutes, and eight people cost £120. You can work it out with your own numbers on our pricing page.

Steer your own bill with two routes

Because there are two rates, you can steer your own bill. Point the number at your VoIP desk phones or the browser phone during the day, so those calls cost 5p a minute. Let it forward to a mobile in the evening or when it is busy, so the premium rate only applies to the calls that genuinely end up there.

That way you only pay 10p when it matters, and you always know where your minutes are going. Your dashboard shows for each call which route it took and what it cost.

When do unlimited calls make sense?

To be fair: for a call centre or a sales team that is on the phone all day, an unlimited plan can work out cheaper than paying per minute. The minutes per person are then so high that a fixed price becomes better value. In that case, check where the fair usage limit sits and whether incoming calls count, because heavy use is exactly where you hit it first.

For most businesses, though, usage is far below that level, and then you are best off paying per minute. You pay for what you use, without small print about normal use. If your team really is on the phone all day, get in touch and we will put together a price that fits.