Twenty-four employees do not tell you how much phone-system capacity to buy. The busiest calling period, the number of configured extensions and the features you need can lead to different license requirements. For an IT owner replacing an office PBX, those details matter more than a headline price per user.
The best IP PBX software depends on which responsibilities you want to retain. FreePBX suits an Asterisk-based system assembled from a free core and optional commercial modules. 3CX offers annual system licensing with deployment choices. VitalPBX packages a free entry edition and paid functionality, while FusionPBX provides a FreeSWITCH-based route with domain-based administration.
This guide is for a small or midsize business's IT generalist or implementation partner who will own the PBX configuration, carrier connection and recovery plan. Recommendations are based on official documentation checked on November 9, 2026; no products were tested. They are conditional choices, not a universal performance ranking.
The purchase behind the product name
An IP private branch exchange manages business extensions and call handling over an IP network. The PBX software is only one component: external calling also needs an appropriate carrier arrangement, numbers and endpoints. A vendor-hosted deployment can reduce infrastructure work without making every telephony responsibility disappear.
If you primarily want a provider-managed calling subscription, start with our VoIP software guide. This comparison instead concentrates on software-level deployment, licensing and administration decisions.
| Software | Suitable operating model | Verified price or license basis | Capacity boundary | Separate purchase to examine |
|---|---|---|---|---|
| FreePBX | IT-owned Asterisk PBX with selected modules | Free core; commercial modules priced separately | No core extension restriction; infrastructure still needs sizing | Hosting, trunks, support and required modules |
| 3CX | Commercial system with hosting choices | 8SC PRO $395/year; optional eligible hosting $295/year | Simultaneous calls and maximum extensions both matter | Carrier service, numbers and partner work |
| VitalPBX | Self-managed PBX with a packaged paid edition | Community free; Enterprise $100/month or $1,000/year | Community 12 extensions; paid capacity remains server-dependent | Hosting and server setup are not supplied by license |
| FusionPBX | FreeSWITCH administration, including multiple domains | Open-source project; optional membership from $100/month | Unlimited extensions is not a server-capacity guarantee | Hosting, carrier service and appropriate support level |
All quoted amounts are USD. These scopes are not equivalent bundles. In particular, a software license, a hosting service and a training/support membership buy different things.
FreePBX: build the bill from the required modules
FreePBX is a web-based management interface for an Asterisk phone system. Its official getting-started material describes extension management, IVRs, backup and restore, and system updates. It places no core restriction on the number of extensions, queues or IVRs you create. That makes it a sensible finalist when you want to control an existing Asterisk-oriented environment without an extension-count license driving every expansion.
FreePBX 17 runs on Debian. The project documents installation on a server or virtual environment, so the relevant workflow is broader than installing a desktop calling app: an administrator provisions the platform, adds extensions, connects the carrier and maintains the resulting system.
The free core is not the same purchase as every capability in the commercial catalog. The add-ons page separately lists products such as Endpoint Manager, Queue Reports and Advanced Recovery. For example, Advanced Recovery is advertised at $440 for a one-year license and describes switching to a secondary server. Do not treat that as an included free-core failover service or assume the license buys the second server.
Migration also deserves a budget line. The FreePBX 17 page says upgrading from a previous version requires a fresh installation followed by transferring data. An existing FreePBX installation therefore does not prove that a major upgrade will be an in-place operation.
Choose FreePBX when an administrator or partner can maintain the operating system, PBX and chosen modules. Compare 3CX when you prefer an edition-based commercial package. If nobody can own upgrades and recovery, reconsider a self-managed purchase rather than assuming the absence of a core license fee makes it cheaper to operate.
3CX: size two limits before choosing an edition
3CX licenses commercial systems annually by edition and simultaneous-call capacity. Its licensing explanation is explicit that both internal and external calls count, and that each capacity tier has recommended and maximum user or extension limits. An idle extension does not use an active call slot, but it still counts toward the extension limit.
That distinction suits an IT-led office that wants a defined commercial system rather than selecting every feature as a separate module. The PRO edition documents call queues, CRM integrations and reporting, with on-premise, self-hosted and 3CX-hosted deployment options. Basic has a different feature scope; do not attach its lower license price to a PRO requirement.
The current official USD price list shows 8SC PRO at $395 annually and eligible 3CX hosting at another $295 annually. The 16SC PRO license is $795, with $450 hosting. These are system-level prices, not monthly rates for each employee. Numbers, SIP trunks and partner services remain separate. The listed 8SC Basic option is self-managed, so vendor hosting should not be assumed available for every size and edition.
Choose 3CX when its supported deployment and edition fit the required workflow, and both capacity limits fit the estate. Compare FreePBX if you want its modular Asterisk route. Obtain the exact device, carrier and integration compatibility confirmation before committing; retaining your current endpoints is an evaluation requirement, not a promise made by the term SIP.
A small office can outgrow a small call license
Consider a hypothetical office with 24 configured users. At its busiest moment, eight external calls and two internal calls are active together. Under 3CX's documented definition, that is ten simultaneous calls, so an eight-call license would not cover this illustrative peak. The actual tier must also satisfy the published extension limit and leave the headroom your business requires.
If a 16SC PRO system meets the final requirements, the published license-plus-hosting components total $1,245 annually: $795 + $450. That is $555 more than the $690 total for the 8SC PRO example. This is arithmetic showing the effect of a different license tier, not a vendor quote for the whole office or evidence of savings against another platform.
Use the same discipline with software marketed as unlimited. Removing a software count restriction does not create CPU, storage, bandwidth or carrier capacity. Ask the implementer to size the expected calling workload, including any recording or other processing that you actually require. Do not turn an extension count into an unsupported hardware recommendation.
VitalPBX: check what changes after the free edition
VitalPBX's current plan page gives Community 12 extensions, unlimited simultaneous calls, limited device provisioning and forum support. The important qualification is that server resources still constrain real capacity. A statement about unlimited extensions elsewhere on the site should not override the named Community plan's limit.
For a business beyond that entry scope, Enterprise is advertised at $100 monthly or $1,000 annually. It lists unlimited extensions and device provisioning, 50 VitXi WebRTC clients, two mobile clients and one tenant, plus ticket and forum support. Those included client counts and the single-tenant scope remain relevant even though the extension entitlement is unlimited.
This package is worth examining when the IT owner prefers a defined set of commercial capabilities over building an add-on list. For example, a branch rollout may need browser calling for a selected staff group rather than mobile licenses for every extension. Quote the actual client mix; the extension allowance alone does not establish the eligible app allowance.
The vendor explicitly says its plans provide licensing, while hosting and server setup remain the customer's responsibility. The one-time Enterprise option is $4,000, and the published terms apply a 25% fee for a major-version upgrade. It should not be described as buying every future major version forever.
Choose VitalPBX when that package and your own infrastructure plan fit. Compare FreePBX for selective modules, or 3CX for its annual system and hosting combination. If multiple isolated tenants are essential, scope the separate Multi-Tenant offering instead of treating Enterprise's one-tenant allowance as a match.
FusionPBX: separate platform control from support access
FusionPBX is a web interface to FreeSWITCH, not another Asterisk interface. Its official documentation describes multi-tenant administration, phone provisioning, unlimited extensions, queues and voicemail-to-email. That makes it particularly worth investigating when the administrator needs domain-based organization and is comfortable maintaining a FreeSWITCH environment.
The project supplies installation guidance and public documentation, with optional paid membership. The membership page starts Green at $100 monthly with no support hours included. Blue is $300 monthly and includes up to 1.5 hours of official support each month. Do not use the cheaper membership headline as the budget for that support allocation.
The standard membership commitment is twelve consecutive months; an exception is stated for people who have paid for and attended official training. Monthly collection therefore does not necessarily mean an unrestricted month-to-month purchase. Review access and application entitlements at the exact membership level you need.
Recovery documentation also reveals the work involved. The official backup guide addresses database and file paths, while the restore guide tells administrators to test recovery on test machines and account for installation-path differences. A database copy alone should not become your assumed complete recovery method.
Choose FusionPBX when its FreeSWITCH administration and domain model solve a real requirement. Compare a packaged commercial option if your team wants a different support and deployment relationship. For a single ordinary office, multi-tenant capability alone is not a reason to take on a platform your administrator cannot maintain.
Take a capacity sheet and a recovery record to the purchase meeting
Use a compact worksheet before accepting a proposal. Record configured extensions, observed peak internal and external calls, required headroom, carrier capacity, supported endpoints, required apps and the exact software edition. Put the source of each number beside it. Leave unknown values unresolved rather than filling them with an assumed industry ratio.
Next, request an isolated recovery demonstration. Record the software version, included configuration and media, required credentials, restore destination, test-call evidence and the person responsible. Use a test environment that will not accidentally register production phones or route real customer calls. The purpose is to establish a recoverable system, not merely confirm that a backup file exists.
Keep license, hosting, trunks, numbers, endpoints, add-ons, support and internal administration as separate cost lines. For example, VitalPBX Enterprise's $1,000 annual license does not include its server, and FusionPBX Blue's $3,600 standard twelve-month membership commitment is not a hosted phone-service quote. No comparison of those figures alone establishes the cheapest complete system.
Stay with the existing PBX if it remains suitable and its support, capacity and recovery arrangements meet the requirement. For a replacement, narrow the field by the operating model: FreePBX for modular Asterisk administration, 3CX for edition-and-capacity licensing, VitalPBX for its defined paid package, or FusionPBX for domain-based FreeSWITCH control. Sign against the completed capacity and ownership record, not the smallest number on the price page.
