Business phone systems range from £5 per user per month to over £200 per user per month — and everything in between, depending on the type of system, the number of users, and how many features you actually need. This guide breaks down every option available to UK businesses in 2026, with real prices and honest advice on what is worth paying for.
The short answer:
- Hosted VoIP is now the most cost-effective option for most UK SMEs: £5–£25/user/month
- Traditional ISDN lines cost £30–£50/channel/month and are being switched off in January 2027 — avoid new commitments
- A 10-person business can have a fully-featured cloud phone system for under £150/month total
- Leased lines (dedicated internet for offices with high call volumes) start at £149/month
- Hidden costs — setup fees, long contracts, call charges — are where buyers get caught out
Why phone system costs vary so much
Two businesses can both say they spend “£20 per user per month on phones” and mean completely different things. The variables are:
- System type: hosted VoIP, on-premise PBX, SIP trunks, Microsoft Teams calling, or traditional PSTN
- Included calls: some plans bundle unlimited UK calls; others charge per minute
- Hardware: IP handsets, softphones (laptop/mobile app), or analogue adaptors
- Contract length: month-to-month versus 12 or 24-month commitments, with corresponding discounts
- Support level: self-service versus dedicated account management
- Add-ons: call recording, CRM integration, call analytics, IVR menus
The cheapest headline price is rarely the cheapest total cost. We will cover both.
Option 1: Hosted VoIP (cloud phone system)
Cost: £5–£25 per user per month
Hosted VoIP is now the standard choice for UK SMEs. Your phone system runs in the cloud, calls route over your internet connection, and you access it via IP handsets, a desktop softphone, or a mobile app. There is no on-site server to buy or maintain.
What affects the price?
Entry-level plans (£5–£8/user/month) typically include:
- A direct dial (DDI) number per user
- Voicemail and voicemail-to-email
- Basic call handling (hold, transfer, call forwarding)
- Mobile app access
Mid-tier plans (£12–£18/user/month) add:
- Unlimited UK landline and mobile calls
- Call recording
- Ring groups and hunt lists
- Auto-attendant / IVR (press 1 for sales, press 2 for support)
- Video calling
Premium plans (£20–£30/user/month) add:
- Advanced call analytics and reporting
- CRM integration (Salesforce, HubSpot, etc.)
- Priority support SLAs
- Multi-site management
Real cost for a 10-person team
| Plan | Per user | Monthly total (10 users) | Annual total |
|---|---|---|---|
| VoIPNinjas Ronin | £5.99 | £59.90 | £718.80 |
| VoIPNinjas Samurai | £14.99 | £149.90 | £1,798.80 |
| VoIPNinjas Shogun | £24.99 | £249.90 | £2,998.80 |
| BT Business Cloud Voice | ~£17 | ~£170 | ~£2,040 |
Most SMEs with 10 users and moderate call volumes land comfortably on a mid-tier plan. A 10-person team with unlimited UK calls, call recording, and voicemail-to-email costs around £1,500–£1,800 per year on hosted VoIP — less than a single traditional ISDN30 circuit per year.
Option 2: SIP trunking
Cost: £5–£12 per channel per month + existing PBX costs
SIP trunking replaces your ISDN circuits with internet-based call lines, but keeps your existing on-site phone system (PBX) in place. If you have invested in a Panasonic, Avaya, or similar PBX and want to extend its life rather than replace it, SIP trunking is the bridge.
Each “channel” supports one simultaneous call. A business handling 10 concurrent calls needs 10 channels, costing £50–£120/month for the SIP trunks alone — plus ongoing maintenance of the PBX hardware.
When SIP trunking makes sense:
- You have a recent PBX with years of life remaining
- Your PBX supports SIP (check with your supplier — many older systems do not)
- You want to migrate away from ISDN before the 2027 switch-off without replacing your whole system
When it does not:
- Your PBX is more than 5 years old (replacing it with hosted VoIP is cheaper long-term)
- You want cloud features (call recording, mobile apps, remote working) — SIP trunking leaves you dependent on the PBX’s feature set
Option 3: Microsoft Teams calling
Cost: £8–£22 per user per month (on top of existing Teams licence)
Microsoft Teams Phone adds full PSTN calling capability to Teams. Users make and receive external calls from the Teams interface, using a business phone number. For businesses already on Microsoft 365, it integrates without a separate app.
The catch: Teams Phone requires either a Microsoft Calling Plan (expensive, limited to certain markets) or a third-party operator connect / direct routing arrangement. The setup complexity and ongoing licensing cost mean Teams calling typically comes out more expensive per user than a standalone VoIP system — unless your business is already paying for an E3 or E5 Microsoft licence that bundles calling.
If your team lives in Teams and you want the calling integrated into the same interface, it is a reasonable choice. If you just want a reliable phone system and Teams is not central to your workflow, a standalone VoIP system at £5–£15/user/month is more cost-effective.
Option 4: Traditional PSTN / ISDN lines
Cost: £20–£50 per line per month — and they are being switched off
Traditional copper phone lines are still running in 2026, but they should not be your planning basis. Openreach is switching off the entire PSTN and ISDN network in January 2027. New ISDN connections have been unavailable since September 2023.
If you are currently on ISDN, you are paying £30–£50 per channel per month for a service that will become obsolete in less than two years. Every month you stay on ISDN, you are overpaying relative to VoIP and deferring a migration you will be forced to make regardless.
Do not sign any new PSTN or ISDN contracts. Migrate now and start saving immediately.
Option 5: Leased lines (for high-reliability requirements)
Cost: £149–£500+ per month for the line, plus VoIP on top
A leased line is a dedicated, symmetrical internet connection — not shared with anyone else. For businesses where call quality and uptime are non-negotiable (medical practices, legal firms, financial services, contact centres), a leased line provides a foundation that standard broadband cannot match.
Leased line pricing depends heavily on your location and required bandwidth:
| Bandwidth | Typical monthly cost |
|---|---|
| 100Mbps leased line | £149–£250/month |
| 500Mbps leased line | £250–£400/month |
| 1Gbps leased line | £350–£600/month |
Leased lines work alongside your VoIP plan — the line provides the connectivity, VoIP provides the phone system. Total cost for a leased line plus 10-user VoIP plan: from around £300/month.
Hidden costs to watch for
Most headline prices omit at least one of the following:
Call charges on “inclusive” plans
Check whether “unlimited UK calls” includes mobile numbers. Many plans bundle landline minutes but charge 3–5p/minute for calls to UK mobiles. If your business calls mobiles frequently, this adds up.
Setup and activation fees
Legitimate VoIP providers charge no setup fee. Some will waive it to close a sale while burying it in the quote. Ask directly: “Is there any activation, setup, or porting fee?”
Number porting fees
Porting your existing numbers to a new provider should be low-cost or free. Some providers charge £15–£30 per number. With VoIPNinjas, number porting is included.
Hardware
IP handsets cost £40–£150 per unit depending on model. If your team is office-based and wants physical phones rather than headsets, budget accordingly. Softphone-only setups (laptop + headset, or mobile app) have no hardware cost.
Contract exit penalties
A 24-month contract with a £50/user/month penalty for early exit on a 10-user team is a £12,000 liability. Always read the exit terms before signing. With VoIPNinjas, you have no exit penalty — 28-day notice, that is it.
How VoIPNinjas is priced
VoIPNinjas keeps pricing straightforward. Three plans, transparent costs, no hidden fees:
| Plan | Monthly cost | Included minutes | Best for |
|---|---|---|---|
| Ronin | £5.99/user/month | 100 min/month | Very small teams or low call volumes |
| Samurai | £14.99/user/month | 750 min/month | Growing SMEs with regular call volumes |
| Shogun | £24.99/user/month | Unlimited + calls to 55 countries | High-volume teams and international callers |
What is always included across all plans:
- 28-day rolling agreement — no long contract
- Free 14-day trial, no card required
- Number porting (existing numbers transferred free)
- Local UK support from our Christchurch team
- Voicemail to email, call forwarding, ring groups, mobile app
What is never included:
- Setup fees
- Exit penalties
- Surprise charges on your first bill
For a 10-person SME on Samurai, the total cost is £149.90/month — £1,798.80/year — with 750 minutes per user included. Step up to Shogun at £249.90/month and get unlimited calls including international calls to 55 countries. Both figures are the complete cost. No add-ons required.
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Frequently asked questions
What is the cheapest business phone system in the UK?
Hosted VoIP is the most cost-effective option for most UK businesses. VoIPNinjas plans start at £5.99/user/month on Ronin (100 min/month). A sole trader or micro-business can have a professional business phone system — DDI number, voicemail, mobile app — for under £10/month.
Is VoIP cheaper than a traditional phone line?
Yes, significantly. A traditional ISDN channel costs £30–£50/month. A VoIP user licence on a comparable feature set costs £5–£15/month. For most businesses switching from ISDN to VoIP, the saving is immediate and substantial.
Do I need to buy new phones to switch to VoIP?
Not necessarily. VoIP works on:
- IP handsets (physical desk phones designed for VoIP) — £40–£150 each
- Softphones (an app on your laptop or PC) — free
- Mobile apps (Android and iOS) — free
- Analogue telephone adaptors (ATAs) — convert existing analogue phones for VoIP use, around £30–£60 each
Most businesses use a mix — a mobile app for staff who are frequently away from their desk, and IP handsets for a reception or main office.
Does VoIP include international calls?
Most VoIP plans include UK calls and charge separately for international destinations. International rates are typically 1–5p/minute to most major countries — significantly cheaper than ISDN international rates. Check your provider’s international rate card before committing.
What internet speed do I need for VoIP?
Each active VoIP call uses approximately 100Kbps of bandwidth. A team of 10 with 5 simultaneous calls needs about 500Kbps dedicated to VoIP — a tiny fraction of a standard broadband connection. The bigger variable is connection stability: a stable 30Mbps connection handles VoIP better than an unstable 100Mbps connection. Your provider should test your connection quality during onboarding.
Are there any ongoing costs beyond the monthly subscription?
With VoIPNinjas, no. The monthly plan covers your licence, support, and standard features. The only variable is call charges if you are on a plan that does not include unlimited calls — and we are transparent about per-minute rates before you sign up.