How much does a business phone system cost in the UK in 2026?

What does a business phone system cost per month?

There are two ways to pay for a modern phone system, and the cheaper one depends on your size.

Fully hosted, per user. Each person has a licence, and the features come with the licence tier. Across the UK market that typically means £10–£20 per user per month for standard features (a number, calls, voicemail, apps, auto-attendant) and £20–£35 for advanced features such as call recording, detailed reporting, queues, CRM integration or contact centre tools. These are general market ranges, not Indigo prices. With Indigo, fully hosted starts at about £10 per user per month for a single handset.

A phone system on SIP trunks. You pay for the phone system (3CX, for example) and for SIP trunk channels: the number of calls that can happen at the same time. A 30-person team rarely has more than a third of its people on the phone at once, so it needs far fewer channels than users. For most businesses, this becomes the more cost-effective option at around 30 users, although the exact crossover depends on how many users you need and which features they use.

The old model, analogue or ISDN lines into a box on the wall, is closing. Openreach shuts the analogue network on 31 January 2027, and wholesale rental on legacy lines has roughly doubled through 2026 (Openreach, July 2026). It's no longer the cheap option, if it ever was.

What would 10, 30 or 60 users cost? A worked example

The table below is an illustration, not a quote. It uses Indigo's hosted starting price and the UK market range for advanced features, and shows where SIP starts to make sense.

Illustrative monthly costs before handsets, installation and out-of-bundle calls. Indigo's prices are quoted excluding VAT. The simultaneous-call figure is a planning assumption, not a rule. A sales or booking team can need far more channels per head than an office of engineers.

Notice what drives the answer. At 60 users on advanced hosted licences, the monthly bill can be three or four times the entry-level figure. If only ten of those 60 people actually need queues and recording, you're paying for features 50 people never use. That's the gap SIP closes. Equally, a 60-person contact centre where everyone needs recording and reporting may be better off hosted.

What one-off and hidden costs should you budget for?

The monthly figure is the headline. These are the costs that make two quotes that look similar turn out very different:

• Handsets and headsets. Many staff don't need a desk phone at all if they use a softphone app or Teams. Buy desk phones for reception, shared spaces and heavy users only.
• Installation, set-up and call flow design. Ask whether building your auto-attendants, hunt groups and out-of-hours routing is included.
• Number porting. Usually simple, but check for charges, especially for multiple numbers or ranges.
• Call bundles. Out-of-bundle calls to mobiles, international numbers and 0845/0870 numbers can add more than the licences. Check what's included.
• Feature add-ons. Call recording storage, wallboards, CRM integration and extra auto-attendants are sometimes separate line items.
• Contract length and exit terms. A low monthly price on a long contract with automatic renewal can cost more than a slightly higher price you can leave.
• Your connection. A cloud phone system needs reliable broadband. If yours is ADSL or needs a landline, budget for SoGEA, broadband without a phone line (about £32 a month with Indigo), or full fibre (£32–£50).

Is your current phone system costing you money? Five signs

If two or more of these apply, a review will usually find savings.

1. You're paying for lines and numbers nobody uses. Over the years, lines get added for a fax, an old alarm, a leaver's direct dial or a site that closed. Nobody cancels them because nobody's sure what they do. Check the bill line by line against what's actually connected.

2. You're still paying legacy line rental. Openreach raised wholesale prices on legacy lines in April and July 2026 and raises them again in October, roughly doubling rental in a year. Every month on copper now costs more than the month before, and after 31 January 2027 remaining lines move to emergency voice access from £35 a month wholesale (Openreach, reported by ISPreview, 24 September 2026).

3. You can't see missed calls. Older systems don't report missed calls, abandoned calls or busy periods, so lost enquiries never show up anywhere. They're lost revenue you can't measure.

4. Every change needs an engineer. If adding a starter or changing the holiday message means a call-out charge, the system is costing you in invoices and in delay.

5. You're on the wrong pricing model for your size. A 60-person business paying advanced per-user licences for everyone, or a 10-person business paying for a phone system and trunks it doesn't need, is overpaying. So is anyone paying out-of-bundle rates on calls that a bundle would cover.

In practice. Supplier price rises that nobody notices are one of the biggest sources of waste. When Indigo reviewed Erskine's IT and telecoms contracts, some legacy suppliers had raised prices by up to 1,200%. We moved Erskine onto better terms and prepared its phone lines, alarms and faxes for the switch-off. Every Indigo phone system review prices both a fully hosted and a SIP option, covers 8x8, 3CX and Microsoft Teams Phone, and arrives as a written recommendation within 2 working days. Book a free phone system review →

How do you compare quotes fairly?

Put every quote on the same basis. Use the same user count and the same feature list, split out users who need advanced features, and compare total cost over the contract term, including handsets, installation and a realistic estimate of call charges. Then ask each supplier the same three questions: what does it cost to add or remove a user, what happens at the end of the term, and who do we call when call quality is poor, the phone provider or the broadband provider? If those are two different companies, expect a certain amount of finger-pointing when something goes wrong.

What to do next

1. Gather your last three phone bills and your contract end date, for every site.
2. List your users in three groups: advanced features, standard calling, and mobile or app only.
3. Identify every line and what's on it, especially alarms, lifts and card terminals. The free PSTN switch-off check walks you through it.
4. Ask for hosted and SIP pricing side by side over the full contract term.
5. Check your mobiles too. Many teams take most business calls on mobiles. A free mobile bill review shows whether you're overpaying there.