Phone System for 20 Employees Australia (2026)

Twenty employees is the inflection point where a basic ISP phone plan breaks. Below 10 staff, a simple hosted VOIP line or two handles most businesses fine. Above 20, you are dealing with departments, shift handovers, and enough simultaneous calls that a misconfigured system costs real money in missed leads. At exactly 20 employees, you are at the boundary. The features that were optional at 10 are now load-bearing. Ring groups stop being nice-to-have and become essential. An IVR auto-attendant stops being a professionalism upgrade and starts being the difference between calls reaching the right person and callers hanging up. This guide covers what a 20-person Australian business actually needs, what it costs in 2026, and the three mistakes that trip up most businesses at this size.

Quick Cost Summary

For a 20-employee Australian business on hosted PBX VOIP in 2026, expect to pay:

• VOIP plan: $30 to $55 per user per month, depending on provider and features. At 20 users that is $600 to $1,100/month all-in.
• Hardware (IP desk phones): $79 to $399 per handset depending on model. Most 20-person offices need 10 to 15 desk phones plus a conference phone.
• Setup: $0 to $500 depending on provider. Many Australian hosted PBX providers include remote configuration.
• Number porting: Free to $50 per number depending on provider.

Total first-year cost: approximately $8,000 to $16,000 including hardware. Ongoing: $600 to $1,100/month.

Why 20 Employees Does Not Mean 20 Phone Lines

The most expensive mistake at this business size is buying one phone line per employee. It sounds logical. 20 staff, 20 lines. But it misunderstands how business calls actually work.

At any given moment, even in a busy office, only a fraction of staff are on live calls simultaneously. A typical 20-person business has peak concurrent call demand of 6 to 10 channels. That accounts for inbound calls to reception, active outbound calls, calls on hold, and transfers in progress. Paying for 20 concurrent channels means paying double or triple your actual requirement.

Hosted PBX systems handle this through a shared channel pool. All 20 users draw from the same pool of simultaneous call capacity. Set the pool at 8 to 10 channels and you cover 99% of scenarios. Monitor your call reports in the first month. If you hit the limit regularly, add channels. If you never hit it, remove some.

Sizing Your System: A Worked Example

Consider a 20-person professional services business: 3 reception/admin staff, 12 consultants or field staff, 3 managers, 2 support staff. Not everyone is in the office at the same time. Consultants are often out on-site. Managers travel. A realistic call model looks like this:

• Reception handling inbound: 2 to 3 channels
• Active consultant calls at peak: 3 to 4 channels
• Outbound sales or support calls: 2 channels
• Calls on hold or in transfer: 1 to 2 channels

Total peak: 8 to 11 concurrent channels. An 8-channel pool with burst capacity to 10 covers this business comfortably. At $2 to $4 per channel per month on a typical hosted PBX plan, the difference between buying 10 channels and 20 channels is $240 to $480 per year. For no practical benefit.

Hosted PBX vs On-Premise: Which Makes Sense at 20 Employees?

For 20 employees in 2026, hosted PBX wins in almost every scenario. The exception is businesses with specific compliance requirements (financial services, healthcare with strict data sovereignty requirements) or businesses with extremely high call volumes where per-minute costs at scale justify on-premise investment.

On-premise PBX made financial sense when call costs were significant. When every minute of PSTN time had a metered cost and an on-site system could arbitrage that. In 2026, Australian hosted PBX plans include unlimited local and national calls. The per-minute arbitrage is gone. The capital cost of on-premise hardware, plus the IT overhead of maintaining it, plus the upgrade cycle cost, rarely pays back at 20 employees. See our full comparison guide on cloud vs office phone systems in Australia for a detailed TCO breakdown.

The Right Hardware Mix for a 20-Person Office

Not every employee needs a desk phone. At 20 employees, hardware decisions should follow role, not headcount. The goal is to match the right device to the right role. Not to standardise everyone on the same handset.

Reception and Front Desk

Reception staff handling inbound call volume need a mid-range to high-end desk phone with multiple line keys. Enough to see and manage several calls simultaneously. The Yealink T46U (8 line keys, colour display) or T54W (16 line keys, large colour screen) are well-suited. Reception staff also benefit from a headset for hands-free operation during high-volume periods. At 20 employees with 2 to 3 reception staff, budget $250 to $400 per handset for reception positions. See our Yealink T46U review and Yealink T54W review for full specs.

Office-Based Staff

Consultants, account managers, and office-based staff who take and make regular calls but do not manage call queues are well-served by a mid-range handset. The Yealink T33G (4 line keys, colour display, under $130) covers most use cases. For staff who handle transfers or need to monitor team call status, step up to the T43U or T46U. Budget $130 to $260 per handset for standard office positions.

Mobile and Remote Workers

Field staff, remote workers, or staff who split time between sites do not need a desk phone. They need a softphone. An app on their mobile or laptop that connects to the same hosted PBX system. Most Australian hosted PBX providers include softphone apps in the plan cost. Remote staff can make and receive calls on their business number from anywhere with a data connection. No hardware purchase required for these roles.

Meeting Rooms

A 20-person business typically has one to two meeting rooms that need a conference phone. The Yealink CP925 (360-degree microphone, connects via USB or SIP, under $540) is the leading AU option for small to medium meeting rooms. For larger boardrooms, the CP965 is worth considering. Budget one conference phone per meeting room. $300 to $600 per unit.

DECT Cordless Phones (Where Relevant)

Warehouse, workshop, or reception environments where staff move around benefit from DECT cordless handsets rather than desk phones. The Yealink W76P base station (supports up to 10 handsets, under $200) is the standard AU choice for VOIP DECT at this scale. If your 20-person business has a floor that is not desk-based, factor in DECT units rather than forcing desk phones into an environment they are not suited for. See our Yealink W76P review.

Recommended Hardware Mix (20 Employees)

Features That Become Essential at 20 Employees

The features that were optional at 5 or 10 employees become load-bearing at 20. Here is the distinction:

Must-Have Features

Ring groups (hunt groups): When a customer calls, the call needs to ring multiple staff simultaneously or in sequence. Not just one person. At 20 employees with 2 to 3 reception staff, if one is on a call, the second should ring automatically. Ring groups handle this. Without them, you are back to a single-line phone system regardless of what else your plan includes.

IVR / auto-attendant: A 20-person business typically has distinct departments or teams. Sales, support, accounts, operations. Callers need to reach the right team without going through a receptionist for every call. An IVR menu ("Press 1 for sales, press 2 for support") routes calls correctly and reduces receptionist load. This was optional at 5 employees. At 20 it is essential.

Call queuing: When all agents in a ring group are busy, calls need to queue with hold music rather than receiving a busy signal. A missed call at a 20-person business is a missed revenue opportunity. Basic call queuing is included in most hosted PBX plans.

Voicemail to email: At 20 employees, calls are coming in across multiple extensions and ring groups. Voicemail messages need to reach the right person's inbox, not sit on a shared device that nobody checks. Voicemail-to-email delivers a recording and transcript to the relevant staff member's email address. Included in most hosted PBX plans at no additional cost.

After-hours call routing: Your system needs to behave differently outside business hours. Divert to voicemail, play an after-hours message, or forward to an emergency mobile. At 20 employees, after-hours call handling is a standard business requirement, not a premium feature.

Nice-to-Have Features

Call recording: Valuable for compliance (financial services, legal, healthcare), training, and dispute resolution. Usually available as an add-on. If your industry has compliance requirements, verify your provider's call recording meets ASIC/APRA/AHPRA requirements before signing up.

Call analytics and reporting: At 20 employees you have enough call volume for reports to be meaningful. Peak hour analysis, missed call rate, average handle time, agent performance. Most hosted PBX plans include a basic reporting dashboard. Use it in the first 60 days to validate your channel and ring group configuration.

CRM integration: If your team uses Salesforce, HubSpot, Zoho, or a similar CRM, a VOIP integration that logs calls automatically and surfaces contact records on inbound calls saves real time. Available from most hosted PBX providers as an add-on or through API integration.

Number porting: If your business has existing numbers (local DID, 1300, or 1800), port them to your new system. You keep the numbers your customers already know. Most Australian hosted PBX providers handle porting at no charge or for a small one-off fee. See our full guide to number porting in Australia.

Features You Do Not Need Yet

SIP trunking: SIP trunks connect an on-premise PBX to the PSTN. If you are on hosted PBX (which we recommend for 20 employees), SIP trunking is not relevant. Your provider handles the carrier connection.

Contact centre features: Skills-based routing, agent wallboards, supervisor monitoring, and workforce management tools are designed for contact centres. Usually 50+ seat operations. At 20 employees you do not need contact centre software. You need a well-configured hosted PBX. Adding contact centre complexity at this size creates cost and overhead without proportionate benefit.

Microsoft Teams Phone / UCaaS: Teams Phone integrates calling into your Microsoft 365 environment. At 20 employees it works, but adds per-user licensing cost (Teams Phone Premium is approximately $27/user/month AUD on top of Microsoft 365 licensing). If your team already lives in Teams and you want calling integrated, evaluate it. If you are not already a heavy Teams user, a standalone hosted PBX is simpler and cheaper. See our Teams Phone guide for a full cost comparison.

Monthly Cost Breakdown: What You Should Actually Pay

The following is a realistic cost model for a 20-person Australian business on hosted PBX in 2026. These figures are based on current Australian provider pricing.

For most 20-person Australian businesses, the mid-range plan ($45/user/month, ~$900/month total) is the right choice. It covers unlimited calls including mobile. Which matters when staff are calling clients' mobiles regularly. And includes the features that matter most at this size. The budget option saves $300/month but requires add-ons for call recording and typically has metered mobile calls. The full-featured tier is worth it only if you have 24/7 support requirements or heavy CRM integration needs.

NBN Connection Requirements

VOIP calls use approximately 85 to 100 kbps of bandwidth per simultaneous call. At 10 concurrent channels, that is roughly 1 Mbps of dedicated VOIP bandwidth. On a standard NBN 50 or NBN 100 connection, this is well within capacity. VOIP bandwidth is a small fraction of your total connection.

The real NBN issue at 20 employees is not raw speed. It is contention and Quality of Service (QoS). If your internet connection is heavily loaded with large file transfers, video conferencing, or cloud backup during business hours, VOIP call quality can degrade. The fix is QoS configuration on your router. Prioritise VOIP traffic (SIP and RTP protocols) over bulk data transfers. Most business-grade routers support this natively. Ask your IT support or your VOIP provider to confirm QoS is configured when you set up.

Number Porting: Keeping Your Existing Numbers

A 20-person business has typically been operating long enough to have established phone numbers that clients and contacts know. Porting those numbers to your new VOIP system is a standard, regulated process under ACMA number portability rules. You have the right to port your number. Your current provider cannot block it.

Porting timeline in Australia is typically 3 to 10 business days for a standard geographic number (02, 03, 07, 08 area codes). Porting a 1300 or 1800 number can take longer. Allow 10 to 15 business days. Run your old and new systems in parallel during the porting window so you do not lose any calls. Your new provider initiates the port. You do not need to contact your old provider first. Use our number porting checker to confirm your number is portable before you start the process.

What Most Businesses Get Wrong at 20 Employees

Mistake 1: Buying 20 lines for 20 people. As covered above, your concurrent call requirement is 6 to 10 channels. Buying 20 is paying double for capacity you will never use. Start at 8 to 10 concurrent channels and scale up based on actual call reports.

Mistake 2: Skipping the IVR because it seems complicated. Setting up an IVR auto-attendant takes 20 to 30 minutes with a modern hosted PBX provider. The payoff. Calls reaching the right team without receptionist involvement. Is immediate. At 20 employees, every call that goes to the wrong department costs someone time. Skip the IVR and you are building that cost into every day of operation.

Mistake 3: Underspecifying reception hardware. The most expensive handsets on this list are the reception desk phones. And they are worth every dollar. A reception staff member managing 3 to 5 simultaneous calls on a phone with inadequate line keys and a small screen is slower, makes more transfer errors, and creates worse caller experiences. The $120 saving from buying a budget handset for reception comes back as lost productivity and frustrated callers. Reception is not the place to cut hardware spend.

Mistake 4: Delaying number porting until after setup. Some businesses get the phone system live first and plan to port their numbers later. The problem is that customers keep calling the old number, calls split between systems, and the porting process creates confusion. Start the porting process on day one of your new system setup. Your VOIP provider can initiate it immediately. The overlap period is short and manageable when planned.

Choosing a Provider: What to Look For

For a 20-person Australian business, the provider checklist is:

• Australian-owned and AU-based support: When your phone system has an issue, you need to speak to someone in an Australian time zone who understands the NBN environment. Offshore support centres are significantly slower to resolve AU-specific issues.
• Hosted PBX included in base plan: Some providers advertise low per-user costs but charge separately for PBX features (ring groups, IVR, call queuing). Confirm these are included before comparing prices.
• Unlimited calls to Australian mobiles: At 20 employees calling clients, mobile-to-mobile call volume is significant. Metered mobile calls on a plan that only includes local and national adds up fast.
• Number porting support: Your provider should handle the porting process end-to-end. If you are told to contact your old provider yourself, that is a red flag. The new provider should initiate and manage the port.
• Trial period or no lock-in contract: A confident provider offers a trial. If you are asked to sign a 24-month contract with no trial, reconsider.

Maxotel is our recommended Australian hosted PBX provider for businesses at this size. Australian-owned, AU-based support, unlimited calls to mobiles included, and PBX features (ring groups, IVR, call queuing, voicemail to email) included in base pricing. See our full guide to best VOIP providers for Australian small businesses for a full provider comparison.

The Setup Process: What to Expect

A well-managed hosted PBX setup for 20 employees takes 2 to 5 business days from sign-up to full operation, assuming your number porting is not time-critical. The sequence:

• Day 1: Sign up with provider, receive SIP credentials, configure your first extensions on the hosted PBX portal. Test softphone apps on mobile devices.
• Days 1 to 3: Configure ring groups, IVR menus, and after-hours routing in the PBX portal. Most providers have a web-based interface. Record your IVR greeting (use a professional voice if client-facing).
• Days 2 to 5: Ship and configure desk phones. IP phones are pre-provisioned by most providers. They arrive ready to plug in and register automatically.
• Days 3 to 10: Number porting runs in parallel. Your old numbers stay active until the port completes.
• Go-live: Once porting completes, all calls come through the new system. Old system can be decommissioned.

Power Outages and Business Continuity

Unlike the old PSTN copper network, VOIP phones require power and an active NBN connection to function. If your office loses power, your phone system goes down unless you have backup power for the NBN connection device (NTD), router, and PoE switch.

The standard mitigation for a 20-person business is a configured call divert rule: if the main office number does not answer within a set number of rings, divert to a mobile number. This costs nothing to configure and ensures you never miss calls during a power outage or NBN outage. Set it up on day one and test it. Your VOIP provider should be able to walk you through the configuration in under 10 minutes.

If your business requires maximum uptime (medical, emergency services, financial trading), consider an uninterruptible power supply (UPS) for your network equipment and a secondary LTE/5G router as a failover connection. The cost is $300 to $800 for the hardware. Your VOIP provider can confirm what is needed for your specific setup.

Emergency Calling (000) on VOIP

VOIP systems in Australia are required to support 000 emergency calls. However, unlike landlines, VOIP emergency calls do not automatically transmit your physical location to the operator. The address registered against your service is used instead. For a fixed office location, register your correct street address with your VOIP provider and confirm it is accurate.

For staff using softphones on laptops or mobiles from variable locations, be aware that the registered address (your office) will be transmitted in a 000 call, not the caller's actual location. Train staff to verbally state their location clearly when making a 000 call from a softphone away from the office.

Your Next Steps

Work through this in order:

1. Audit your current setup. List every phone number your business uses, every device currently connected, and every third party that uses your phone line (alarms, EFTPOS, fax). These all need a migration path.
2. Map your call flows. Who needs to ring when a customer calls? What happens after hours? What do you do with missed calls? Sketch this before speaking to a provider. It determines your IVR and ring group configuration.
3. Decide your hardware requirements. Use the role-based table above. How many desk phones, what models, how many meeting rooms, any DECT needs?
4. Get a quote. Use our VOIP Cost Calculator to estimate your monthly cost, then get a confirmed quote from a provider.
5. Initiate porting early. Once you decide on a provider, start the number port immediately. It runs in parallel with your setup and is usually complete before your system is fully configured.
6. Configure before cutting over. Run old and new systems in parallel during setup. Only cut over once you have tested every ring group, IVR path, and divert rule.

Related reading:

• Phone system for 10 employees
• Best phone system for small business Australia
• Cloud vs office phone system
• Number porting in Australia