VoIP Phone System for Accountants: Features, Costs and Setup

Last updated: April 2026

Accountancy practices have a complicated relationship with their phone system. For most of the year, phones ring at a manageable pace. Clients call with queries, you call HMRC, partners take calls from their desks. Then January arrives. Self Assessment deadline. The phones go from manageable to relentless overnight, and suddenly every limitation of your phone system is exposed.

Missed calls from clients who cannot get through. No way to tell who called while you were on another line. Voicemails piling up. Partners sharing a single main number when they each need their own direct line. No call recording when a client disputes what was agreed on the phone. And the underlying fear: if you are still on a traditional landline, it stops working entirely when the PSTN switch-off completes in January 2027.

VoIP fixes all of this. Not in a vague "technology solves everything" way, but in specific, practical ways that directly address the problems accountancy practices actually face. This guide covers exactly what a VoIP phone system does for accountants, what it costs for a typical practice, which features matter most, and how to get set up without disrupting your workflow.

At Compare The Networks, we have set up VoIP systems for accountancy firms across the UK since 2008. We understand the specific requirements of practices, from sole practitioners to 50+ staff firms. We are OFCOM regulated and rated 4.3/5 on Trustpilot from 1,000+ reviews.

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Why Accountancy Practices Need a Proper Phone System

Accountants are not call centres. But you are more phone-dependent than many practices realise. Think about a typical day:

• Clients calling with questions about their accounts, tax returns, or payroll
• You calling HMRC (and spending 40 minutes on hold, but that is another story)
• Partners taking calls from key clients who expect to reach their named contact directly
• Reception fielding calls and routing them to the right person
• Bookkeepers and payroll staff handling queries from clients' employees

When the phone system works well, this all flows smoothly. When it does not, you get bottlenecks. Clients get engaged tones. Messages get lost. Partners cannot be reached. And during peak periods (January for Self Assessment, July for corporation tax), the problems multiply.

A traditional phone line gives you one line per physical connection. If you have three lines and four people are trying to call at once, the fourth person gets an engaged tone. A VoIP system gives you as many simultaneous calls as your broadband can handle (typically 20+ on a standard connection). No engaged tones. No missed clients.

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The Features That Actually Matter for Accountants

Not every VoIP feature is relevant to an accountancy practice. You do not need a 500-seat contact centre or AI-powered chatbots. You need reliability, professionalism, and a few key features that make your practice run better. Here is what matters.

Direct Dial Numbers (DDIs) for Each Partner

Every partner and senior staff member should have their own direct dial number. When a client calls their accountant, they want to reach that specific person, not navigate a menu or explain their situation to reception first.

With VoIP, each partner gets a DDI (a unique phone number that goes straight to their extension) at a cost of GBP1 to GBP3 per month per number. Clients save the direct number. Calls go straight through. If the partner is unavailable, the call can route to their voicemail, their mobile, or to a colleague, automatically.

This is one of the simplest changes that has the biggest impact on client satisfaction. Clients feel like they have a direct line to their accountant. Partners feel like they are running a professional operation. Win, win.

Call Recording for Compliance and Dispute Resolution

Accountants give advice over the phone constantly. Tax planning conversations. Payroll instructions. Year-end discussions. When a client later says "you told me I could claim that expense" or "you never mentioned that deadline," having a recording of the actual conversation is invaluable.

Call recording on VoIP is automatic. Every call (inbound and outbound) is recorded, stored securely in the cloud, and searchable by date, number, or extension. Most providers store recordings for 12 months as standard, with options to extend.

Under GDPR, you need to inform callers that calls are recorded. A simple auto-attendant announcement ("calls may be recorded for training and compliance purposes") handles this. Your practice should also have a data retention policy covering how long recordings are kept and who can access them.

Beyond dispute resolution, call recordings are useful for training junior staff, reviewing how client queries are handled, and maintaining an audit trail for professional indemnity purposes.

Auto-Attendant (IVR)

An auto-attendant answers your phone automatically and routes callers to the right department or person. For an accountancy practice, a simple menu works well:

• Press 1 for accounts and tax
• Press 2 for payroll
• Press 3 for bookkeeping
• Press 0 to speak to reception

This means callers reach the right team without reception having to answer and transfer every call. During busy periods like January, when your receptionist is already overwhelmed, the auto-attendant handles the routing automatically.

You can also set different menus for different times of day. During office hours, callers get the normal menu. Outside office hours, they hear a message with your opening times and can leave a voicemail. During the Self Assessment crunch, you could add a specific option: "If you are calling about Self Assessment, press 1."

Out-of-Hours Routing

Accountancy practices keep regular hours. But clients do not always call during those hours, especially individuals who work during the day and can only call in the evening. With VoIP, you can set up intelligent out-of-hours routing:

• During office hours (say 9am to 5:30pm): calls ring through to extensions as normal
• Outside hours: calls go to a voicemail greeting with your opening times, and the voicemail is emailed to you as an audio file so you can pick it up on your phone
• Urgent overflow: calls can be forwarded to a partner's business mobile if needed

You can also set specific rules for specific numbers. If your biggest client calls after hours, you might want that call to go straight to the partner's mobile. Everyone else gets voicemail. VoIP makes this easy to configure.

Ring Groups and Hunt Groups

During peak periods, you might want multiple staff to be available to answer calls. Ring groups let you set this up. When a call comes in to your main number, it can ring:

• All at once (all phones in the group ring simultaneously, first to answer gets the call)
• In sequence (rings person A for 15 seconds, then person B, then person C)
• Round-robin (distributes calls evenly across the group)

For a tax department handling Self Assessment queries in January, a ring group means the first available person picks up. No clients stuck on hold. No calls going to voicemail unnecessarily.

Mobile App

Partners and managers do not sit at their desks all day. Client meetings, HMRC visits, tribunal hearings, working from home. A VoIP mobile app means they can make and receive calls on their business number from anywhere.

The caller sees the business number, not the partner's personal mobile. Calls are logged in the system. Call recording still works. And if the partner is in a meeting, the call rolls over to voicemail or a colleague just like it would on their desk phone.

This is particularly useful for practices that offer flexible or hybrid working. Staff can work from home with the same phone system as the office, same number, same features, same call recording.

CRM and Software Integration

Modern VoIP platforms can integrate with accounting and practice management software. The most relevant integrations for accountants:

• Xero: Click-to-call from Xero contacts. Incoming calls show the Xero contact record on screen.
• Sage: Similar integration for Sage users.
• Practice management software: Many platforms integrate with tools like CCH, Iris, and TaxCalc, though the depth of integration varies.
• Microsoft 365: Integration with Teams, Outlook calendar (show busy/available status), and contacts.

Screen pops are particularly useful. When a client calls, their details appear on screen before you even answer. You know who is calling, which partner handles their account, and what their recent activity looks like. It makes every call feel personal and prepared, even when you are juggling 20 things.

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What a VoIP System Costs for a Typical Practice

Let us work through some real numbers for different practice sizes. All prices are ex VAT.

3-Person Practice (Sole Practitioner + 2 Staff)

Or about GBP28 per person per month for a complete professional phone system with call recording, auto-attendant, mobile app, and a direct line for the partner.

8-Person Practice (2 Partners + 6 Staff)

About GBP19 per person per month. The per-user VoIP cost drops at 5+ users with most providers.

15-Person Practice (3 Partners + 12 Staff)

About GBP16.50 per person per month. At this scale, VoIP is dramatically cheaper than maintaining a traditional PBX system with multiple ISDN lines. Get an exact quote for your practice size.

Compared to a Traditional Phone System

For a 10 person practice, a traditional PBX with ISDN, maintenance, and call charges typically costs GBP400 to GBP600 per month. VoIP for the same practice costs GBP150 to GBP200 per month. That is a saving of GBP2,400 to GBP4,800 per year, every year.

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Seasonal Considerations: Planning for January and July

Accountancy is a seasonal business. The phone is busier at some times of year than others, and your phone system needs to handle the peaks.

January (Self Assessment Deadline)

The last two weeks of January are intense for most practices. Call volume can increase by 200% to 300%. Clients who have been ignoring their tax return for 10 months suddenly want urgent help.

How VoIP handles this:

• No capacity limits. Unlike traditional lines where 3 lines means only 3 simultaneous calls, VoIP handles as many calls as your broadband supports. On standard 80/20 broadband, that is 20+ simultaneous calls.
• Ring groups. Route Self Assessment calls to all available tax staff, not just one person.
• Auto-attendant update. Add a specific Self Assessment option to your menu. Record a message with key deadlines and online submission links, which may answer the question without needing a person.
• Overflow to mobiles. If all desk phones are busy, overflow calls to staff mobile apps so they can pick up from anywhere.
• Call queue. Instead of an engaged tone, callers wait in a queue with hold music and position announcements. They stay on the line instead of hanging up and trying a competitor.
• Temporary staff. Adding temporary extensions for seasonal staff takes minutes, not days.

July (Corporation Tax / Year-End)

Less frantic than January, but still a busy period for practices handling corporation tax and year-end accounts. The same features apply. The advantage of VoIP is that you do not need to do anything special. The system scales automatically. You are not paying for extra lines that sit idle for 10 months of the year.

August and December (Quieter Periods)

During quieter periods, VoIP still earns its keep. Partners working from home or on holiday can take calls on the mobile app. Out-of-hours routing catches calls from clients in different time zones. And you are not paying for unused ISDN channels.

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Client Confidentiality and Security

Accountants handle sensitive financial data. Client confidentiality is not optional, it is a professional obligation. Your phone system needs to reflect that.

Call Encryption

Modern VoIP systems encrypt calls using SRTP (for audio) and TLS (for signalling). This means the contents of your calls cannot be intercepted as they travel across the internet. Make sure your provider has encryption enabled by default.

Secure Call Recording Storage

Call recordings are stored in the cloud on your provider's secure servers. Access is controlled by user permissions, so only authorised staff can listen to recordings. Recordings should be encrypted at rest as well as in transit. Check your provider's security certifications (ISO 27001 is the gold standard).

Access Controls

VoIP admin portals let you control who can do what. Partners can access all call recordings. Staff can only access their own. Reception can transfer calls but cannot listen to recordings. Junior staff might have limited outbound calling to prevent misuse.

Professional Indemnity

Call recordings provide an audit trail that supports professional indemnity claims. If a client alleges negligent advice was given over the phone, you have the recording. Many PI insurers view call recording favourably as a risk management measure.

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How to Switch Without Disrupting Your Practice

Switching phone systems sounds disruptive. It does not have to be. Here is how we do it for accountancy practices.

Step 1: Assessment (Day 1)

We review your current phone setup, broadband speed, number of users, and feature requirements. We check your broadband upload speed and latency to make sure it can handle VoIP. If your broadband needs upgrading, we arrange that first (usually Sky SOGEA 80/20 at GBP35+VAT).

Step 2: Configuration (Days 2 to 4)

We set up your VoIP system: extensions for each staff member, DDIs for partners, auto-attendant menu, ring groups, out-of-hours routing, call recording settings, and voicemail. We configure and test each desk phone or softphone before sending them to you.

Step 3: Number Porting (Days 5 to 20)

We submit a port request to move your existing phone number(s) to the VoIP system. This takes 10 to 15 working days. During this period, your old phones continue to work. On the port date, the number switches over seamlessly. We give you a temporary number to use immediately if you want to start using the VoIP system before the port completes.

Step 4: Go Live (Port Day)

On the day the number port completes, your VoIP system takes over. We monitor everything closely for the first few days to catch any issues. We are on the phone if you need us.

Best Time to Switch

Avoid switching in January or the first two weeks of July. The best time for most accountancy practices is February to May or August to November, when call volumes are lower and you have breathing room to get comfortable with the new system.

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VoIP Platform Comparison for Accountants

Different VoIP platforms suit different practice sizes. Here is how the main options compare:

We most commonly recommend 3CX for accountancy practices because of its strong feature set, competitive pricing, good CRM integrations (including Xero and Sage), and the fact that we can manage and support it directly for you. But the right choice depends on your specific needs. Get in touch and we will recommend the best platform for your practice.

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Frequently Asked Questions

Can I keep my existing phone number when switching to VoIP?

Yes. We port your existing number to the VoIP system. It takes 10 to 15 working days, and during that time your old phone continues to work normally. On the port day, the number moves over seamlessly. Your clients will not notice any change except better call quality and a more professional experience when they ring.

What happens if our internet goes down?

Your desk phones will stop working, but calls do not get lost. VoIP systems can be configured to automatically forward calls to business mobiles when the internet is down. Your staff can also use the VoIP mobile app over 4G or 5G. We also recommend a small UPS (GBP80 to GBP150) to keep your router running during short power cuts. For practices where phones are absolutely critical, a backup 4G broadband connection (around GBP25 per month) provides a second internet path.

Is call recording GDPR compliant?

Call recording is legal for UK businesses, but you must comply with GDPR. You need to inform callers that calls are recorded (an auto-attendant announcement is sufficient), store recordings securely with controlled access, have a data retention policy, and be able to delete specific recordings if a data subject access request requires it. All mainstream VoIP providers build these capabilities into their platforms.

Can we integrate VoIP with Xero or Sage?

Yes. Platforms like 3CX offer integration with Xero and Sage. The integration enables click-to-call from your accounting software, screen pops showing the client's record when they call, and automatic call logging. The depth of integration varies by platform, so ask us which option gives the best integration for your specific software stack.

How many calls can we handle simultaneously?

On standard 80/20 broadband, you can handle 20+ simultaneous VoIP calls. Even for a 15 person practice in peak January, you are unlikely to have more than 8 to 10 calls happening at once. You will never run into the capacity limits that traditional phone lines impose. If you are concerned about broadband capacity, our broadband guide covers what you need.

What phones do you recommend for an accountancy practice?

For partner offices, we recommend the Yealink T46U or T48U. These are professional-grade desk phones with large colour displays, excellent audio quality, and support for multiple lines and DDIs. For general staff, the Yealink T33G offers great value at around GBP60 to GBP70. For reception, the Yealink T54W with expansion modules lets you see at a glance which extensions are busy and transfer calls with one touch. All can be leased from GBP3 to GBP5 per month per phone to keep upfront costs low. See our VoIP troubleshooting guide if you experience any issues with your handsets.

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Ready to Upgrade Your Practice's Phone System?

If your accountancy practice is still on traditional phone lines, or on a VoIP system that is not delivering what you need, we can help. We have been setting up phone systems for UK businesses since 2008, and we understand what accountancy practices need: reliability, compliance features, professional call handling, and the ability to handle January without breaking a sweat.

Get a free VoIP quote tailored to your practice. Tell us how many staff you have, what features matter to you, and we will come back with a recommendation and a price. No obligation. No pressure. Just honest advice from people who know telecoms.

Compare The Networks. OFCOM regulated. 4.3/5 on Trustpilot from 1,000+ reviews. Helping UK businesses get their phones right since 2008.