Best VoIP Phone Systems for UK Small Businesses

Do small businesses still need a phone system?

Yes, but it no longer has to mean a beige box screwed to the office wall and a desk phone for every employee.

Modern VoIP systems can put the same business number on a desk phone, laptop and mobile app. Calls can follow staff between the office, home and customer sites, while features such as call queues, voicemail-to-email, recording and CRM integration are managed online.

That is especially useful for smaller businesses because the person answering sales calls may also be the person doing the accounts, visiting customers and making the tea.

If you are comparing the broader options first, see our business phone systems guide and our explanation of PBX phone systems.

The UK phone network switch-off is now a business deadline

The old UK Public Switched Telephone Network, along with ISDN and other analogue services, is scheduled to close on 31 January 2027.

That is no longer a distant telecoms story. In July 2026, Openreach estimated that around 350,000 business premises still needed to migrate and around 1.5 million lines were still operating on the old copper-based phone network.

BT also points to Ofcom data showing a 45% increase in significant PSTN resilience incidents during 2024.

If your business still relies on an old analogue or ISDN phone system, 2026 is the year to sort it rather than waiting for January.

What exactly is VoIP?

VoIP stands for Voice over Internet Protocol. In plain English, your calls travel using IP networks rather than the old analogue telephone network.

The business number still looks like a normal number to customers. They do not need a special phone to call you.

Your staff might answer on:

• a traditional-looking IP desk phone;
• a computer headset;
• a smartphone app;
• a browser;
• Microsoft Teams or another collaboration platform.

Is SIP the same as VoIP?

No. The terms are often used together, which is why they get muddled.

VoIP is the broad idea of carrying voice over IP networks. SIP, or Session Initiation Protocol, is one of the technologies commonly used to set up and manage those communications.

You do not need to become a telecoms engineer to buy a phone system. Just know that a supplier talking about SIP trunks may be describing a different way of connecting an existing phone setup than a fully hosted cloud VoIP service.

Hosted VoIP or on-premise PBX?

For most small businesses buying a new system today, hosted VoIP is the simpler route.

The provider runs the core phone platform in the cloud. You pay per user or licence and manage users online. There is no office phone server for you to maintain.

An on-premise or hybrid PBX can still make sense for larger or more complex sites, but the small-business case is weaker unless there is a specific technical reason.

What does VoIP cost for a small business?

A sensible starting range is roughly £8 to £25 per user per month for mainstream cloud-phone software, before adding hardware, premium features, specialist integrations or unusual call charges.

For a five-person business:

The important question is what is included. A £10 licence that needs separate call bundles, desk-phone rental and recording can easily cost more than a £15 licence where those items are included.

RingCentral: best all-round option

RingCentral remains one of the strongest general-purpose cloud phone systems because it combines business calling, messaging and video around the same user account.

Its current UK business-VoIP page advertises plans from £7.99 per user per month, with higher tiers adding more outbound minutes, larger meetings, internet fax and automatic call recording.

For a five-to-20-person business, RingCentral makes sense when you want something that can start with ordinary business calling and grow into a wider communications platform.

Vonage: easiest pricing to understand

Vonage currently publishes a particularly simple UK ladder:

• Express: £10/user/month.
• Core: £15/user/month.
• Max: £25/user/month.

Express is built around essential calling, while Core adds unlimited outbound calls, CRM integration and Microsoft Teams compatibility. Max adds a more mobile-first proposition including eSIM-related features.

If you are a small business owner who just wants to know “what does the next level cost?”, that clarity is refreshing.

HiHi: strong for businesses that still want a proper desk phone

Not every business wants staff talking into laptops all day.

HiHi combines a modern touchscreen desk phone with mobile and web working, and positions itself as UK-designed and UK-supported. It now also promotes AI-powered call insights.

This can be a better cultural fit for estate agents, recruiters, accountancy firms and other offices where the desk phone is still a genuine working tool rather than office furniture.

Microsoft Teams Phone: best if Teams is already open all day

If everyone in the business already spends the working day in Microsoft Teams, moving external phone calls into the same application can remove an extra system.

Microsoft currently lists Teams Phone Standard at £7.70 per user/month when paid yearly. The UK domestic calling option is £13.10 per user/month and includes 3,000 outbound domestic minutes for UK users.

Be careful comparing that £7.70 directly with an all-inclusive VoIP quote. Teams Phone Standard is the phone-system layer and you still need the appropriate Teams licence and a route onto the public telephone network.

8×8: useful if customer-service requirements are getting serious

8×8 makes more sense when “we need a phone system” is gradually becoming “we need proper customer communications”.

Its platform spans cloud calling and collaboration through to richer contact-centre functionality.

That can be valuable for a growing support or sales team. For a three-person building firm that wants a main number and call forwarding, it may be unnecessary complexity.

Dialpad: interesting for teams that want AI around calls

Dialpad has leaned heavily into AI-powered calling features such as real-time transcripts and automated call summaries.

That can be useful for sales calls, recruitment interviews and customer-service conversations where nobody wants to spend another ten minutes writing notes after hanging up.

The value depends on whether your team will actually use those features. Do not pay for AI summaries if your entire phone requirement is “make it ring on Dave’s mobile when nobody is in the office”.

BT Cloud Voice: familiar provider, but read the commitment

BT Cloud Voice is a credible option for businesses that want voice and connectivity from a major UK provider.

Current published monthly licence prices are £10.52 for Basic, £13.74 for Connect and £20.09 for Collaborate.

The important part is the small print: those public prices are shown against 60-month licence terms, with scheduled annual pounds-and-pence price increases.

A five-year agreement is a very different buying decision from a flexible month-to-month cloud subscription. Compare the full commitment, not just £10.52 versus £15.

What features does a small business genuinely need?

Most businesses do not need 80 phone features. They need eight that work reliably.

• Number porting: keep the business number customers already know.
• Call forwarding: move calls to mobiles or another location.
• Auto attendant: “Press 1 for sales, 2 for accounts” where useful.
• Call queues: avoid losing calls when several customers ring together.
• Voicemail-to-email: useful when nobody sits next to the handset.
• Mobile and desktop apps: essential for hybrid and field staff.
• Call recording: useful where training, quality or compliance requires it.
• CRM integration: valuable if the business lives in HubSpot, Salesforce or another CRM.

Will VoIP work on your existing broadband?

Usually, yes, provided the connection is reliable.

The old idea that VoIP is massively “data intensive” is misleading. Voice calls do not normally consume huge amounts of bandwidth compared with video meetings or large file transfers.

What matters more is quality and consistency: latency, packet loss, Wi-Fi congestion and whether the internet connection keeps dropping out.

A fast connection that randomly disappears for 30 seconds six times a day can be worse for phones than a slower but rock-solid one.

What happens when the internet goes down?

This is the main operational weakness of cloud telephony.

If the office internet connection fails, desk phones using that connection may stop working. A properly configured system can route calls to mobile apps or alternative numbers, but those fallbacks need to be planned before the outage.

Also remember power. Traditional analogue lines could sometimes continue during a local power cut. IP phones, routers and fibre equipment need electricity.

Can you keep your existing business number?

In most migrations, yes. Number porting lets you move an existing business number onto the new provider.

Do not cancel the old service before the port has been agreed. The provider should manage the sequence so you do not accidentally lose a number printed on vans, invoices and Google Business Profile.

VoIP benefits for a small business

How to compare VoIP quotes properly

Send every provider the same requirement. Otherwise one quote includes call recording and desk phones while another does not, and the comparison becomes meaningless.

Give them:

1. number of users now;
2. number of users you expect in 12 to 24 months;
3. existing business numbers that need porting;
4. whether staff need desk phones, mobile apps or both;
5. estimated outbound calling;
6. international destinations if relevant;
7. need for recording, queues and auto attendant;
8. CRM or Microsoft Teams integration;
9. required support hours;
10. preferred contract length.

What should the quote include?

• monthly licence price per user;
• included call allowance;
• desk-phone purchase or rental;
• setup and number-porting fees;
• call recording and storage;
• CRM integration costs;
• support charges;
• contract length and break fees;
• annual price-rise mechanism;
• cost of adding and removing users.

Watch the contract when your headcount changes

Cloud telephony is technically scalable. Your contract may be less flexible.

Providers are normally delighted to add ten users when the business grows. The better question is what happens when you lose a large contract and need to remove ten licences.

Ask whether you can reduce user numbers mid-term and whether minimum licence commitments apply.

Hosted VoIP vs mobile-only business numbers

A two-person trade business may not need desk phones at all. A cloud number that rings two mobiles could solve the entire problem.

Once you have reception, departments, call queues, customer-service staff or reporting requirements, a fuller business phone system becomes easier to justify.

Buy the system for the business you run, not the 100-person company you hope to become.

Checklist before the January 2027 switch-off

• Identify every analogue or ISDN line at each premises.
• Check what is plugged into those lines besides phones.
• List the numbers that must be retained.
• Check broadband reliability and backup arrangements.
• Test alarms, door entry, lifts, CCTV and old payment equipment separately.
• Choose and test the new phone system before cancelling anything.
• Plan number porting.
• Train staff on the new apps and call handling.
• Document what happens during a broadband or power outage.