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 that comes in over the internet on a softphone or desk phone is free, and calls you place over the internet to the UK, Europe and the United States cost 5p a minute. We bill per second. 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 there is no minute cap to go over and no bundle to use up. Reasonable use does apply: if you structurally make very large volumes, as a call centre for example, we agree a custom price with you rather than surprise you afterwards. 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. Menus and queues 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 Customer Service, which costs £43 a month for up to eight people. If the team together makes the average 113 minutes, that adds £0 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 £0 to £25 in minutes, so £43 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. On our VoIP Phone System the same four people pay £52 a month, with unlimited calls over the internet subject to fair use, but without forwarding to a mobile or landline. All prices are on our pricing page.

Steer your own bill with two routes

Because the route sets the price, you can steer your own bill. Point the number at your VoIP desk phones or the browser phone during the day, so those calls are free. 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: sometimes a fixed price is simply easier. If your team has a good internet connection, in the office and at home, and your staff call customers regularly, you may not want to count minutes every month. That is what our VoIP Phone System is for: £13 per employee a month, unlimited calls over the internet to UK and EU landlines and mobiles, subject to fair use. For us, fair use means normal business calling by your own staff: no call centre, no autodialler and no resale. If we see very high volumes month after month, we get in touch and agree a proposal with you.

The difference from the plans is the route. On the VoIP Phone System everything runs over the internet, so if your connection drops, the phone does not ring. On the plans a call can also be delivered over the fixed and mobile networks, and you pay per second for what you call. For a support, help or emergency line that must always get through, and for teams that rarely dial out, that is the better choice.

If your team is on the phone all day, as in a call centre or an outbound sales team, neither standard option fits well. Get in touch and we will put together a price that suits that volume.