In short
3CX is a software VoIP phone system (an IP PBX) that can be hosted by 3CX, self-hosted in your own cloud account or installed on-premise. It comes in four editions, SMB Free, Basic, PRO and AI. Commercial editions use one flat annual licence per system, sized by simultaneous calls, and you connect it to a SIP trunk of your choice.
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3CX as a VoIP PBX
A PBX is the switching system behind a business phone system: it gives every user an extension, routes incoming calls through menus and groups, and connects calls to the outside world. 3CX is a PBX built entirely in software and based on SIP, the signalling protocol most VoIP equipment speaks. That is what makes it a "3CX VoIP" system: calls travel as data from the moment they leave a phone or app.
On top of extensions, ring groups and voicemail, 3CX adds call queues, call recording, reporting, web, Windows and mobile apps, video meetings and website live chat on the editions that include them. Two things set it apart from most cloud phone systems:
- It is licensed per system, not per user. Commercial editions use one annual licence for the whole system, sized by how many calls run at once
- It does not bundle numbers or minutes. You connect it to a SIP trunk of your choice, which keeps your numbers portable
If the terms are new to you, our explainers on PBX vs VoIP and SIP vs VoIP cover them in plain English.
Where 3CX runs: three deployment choices
3CX describes three ways to deploy it: hosted by 3CX, self-hosted in your own cloud, or on-premise. The edition sets the features; the deployment decides who looks after the server.
| Deployment | Where the 3CX VoIP server runs | Who looks after it | Often suits |
|---|---|---|---|
| Hosted by 3CX | 3CX's own hosting, a separate annual charge (included with SMB Free). Not offered for Basic at 8 simultaneous calls or for systems of 384 and above | 3CX runs the hosting; we can manage the configuration | Organisations that want no servers at all |
| Self-hosted in your cloud | Your own account with Amazon, Microsoft Azure, Google or DigitalOcean, on Windows or Linux | You or we manage the virtual machine, backups and updates | IT teams that want control of the cloud account and data location |
| On-premise | A Windows or Linux server, or a supported virtual platform, on your site | You or we manage the hardware and operating system | Sites with a server estate or a need for local call handling |
Our sister site covers the cloud options in depth on its hosted 3CX page. If you are weighing cloud against a server on site more generally, see hosted vs on-premise phone systems.
Not sure which edition fits? Ask us
Tell us what you need and we will recommend the right edition for your organisation, with a quote.
3CX editions in one line each
| Edition | In one line |
|---|---|
| SMB Free | For small offices of up to 10 users, hosted by 3CX, with apps, call handling, live chat and messaging |
| Basic | Dependable core telephony, routing, apps and basic reporting, without call queues, recording, CRM or bridges between offices |
| PRO | Adds call queues, recording, wallboards, CRM and full Microsoft 365 integration, multi-site and AI voicemail transcription |
| AI | Adds AI Agents, call transcription, summaries and sentiment, skill-based routing and, from 16 simultaneous calls, failover and the Teams Direct Routing integration |
The edition sets the features; the simultaneous-call size sets the capacity. For the full feature-by-feature table, see 3CX editions on our sister site. Small teams comparing 3CX with other options should also read VoIP phone system for small business.
How 3CX licensing works
3CX calls it licensing per system, not per seat. A commercial licence is one flat annual price for your whole 3CX system, set by two choices: the edition, and the number of simultaneous calls (SC) the system can carry. Commercial editions start at 8 SC.
- Both internal and external calls count. Two colleagues talking extension to extension use capacity, just like a call to a customer.
- Idle extensions use nothing. Capacity is only used while calls are live, which is why 50 users do not need 50 licences.
- User limits still apply. Each SC size has a recommended range of users or extensions and a hard maximum, so the licence must fit your call peak and your system size.
- Size with headroom. 3CX's own example: if your busiest moment has 16 calls live at once, assess a 24 SC licence for busy days and growth.
Hosting, SIP trunks, numbers and handsets are separate from the licence. Our sister site explains it further on its 3CX pricing page, and VoIP phone system cost compares the 3CX model with per-user platforms. For prices, ask us for a quote.
Is 3CX the right fit for you?
We will check it against your systems and requirements and recommend the right option.
SIP trunks and 3CX VoIP providers
3CX connects to the public phone network through a SIP trunk, and you choose the provider. 3CX publishes a directory of SIP trunk providers by country, with the United Kingdom listed. Each provider is marked either "3CX Tested", where 3CX completed the testing itself, or "VoIP Provider Tested", where the provider ran the tests and 3CX reviewed the results. Listed providers come with pre-configured templates inside 3CX for a quicker set-up. Community templates also exist, but they have not been through the same process and are not in the directory.
Choosing the trunk is as important as choosing the edition. We look at how many channels or simultaneous calls you need, whether your numbers can move across, and how the trunk handles your call volumes and international dialling. Your existing numbers can normally be ported to the new trunk; see port your landline number to VoIP, and our sister site's guide to SIP trunk providers.
Phones, apps and devices for 3CX
3CX works with a wide range of apps and devices:
- Web client in the browser for calls, chat, presence, voicemail and queue tools, with nothing to install
- Windows, iOS and Android apps, so an extension rings on a laptop or mobile anywhere without giving out a personal number
- Desk phones from the manufacturers on 3CX's supported IP phones list, including Fanvil, Snom and Yealink, provisioned from the admin console. See VoIP desk phones
- DECT, door phones and analogue adapters from 3CX's supported lists, for warehouses, entrances and older devices. See VoIP adapters
Handsets can be bought outright or, in some cases, included in your monthly rental, with the options confirmed at quote. Existing IP phones can often be reused if they are on 3CX's supported list; we can check them before you switch. Our VoIP handsets for business hub covers the wider choice.
3CX with Microsoft 365, Teams and your CRM
- Microsoft 365: Basic syncs users and supports single sign-on; PRO and AI add full Microsoft 365 and Google Workspace integration, including presence sync with Teams
- Microsoft Teams: the AI edition at 16 simultaneous calls and above includes a Teams Direct Routing integration, so Teams users can make and take calls through 3CX. See Microsoft Teams VoIP
- CRM: PRO and AI include CRM integration with caller lookup, contact creation and call journaling. See VoIP CRM integration
- Recording: SMB Free, PRO and AI include call recording, and AI adds transcription and sentiment. See VoIP call recording
Network and security matter as much as features. 3CX advises disabling SIP ALG on your router, and a 3CX system should sit behind a well-configured firewall with strong passwords and limits on international dialling. See VoIP router settings and VoIP security.
How we help with 3CX
- Discovery. We look at your users, sites, busy periods, existing handsets and integrations.
- Edition, size and deployment. We recommend an edition and simultaneous-call size with sensible headroom, and where 3CX should run.
- SIP trunk and numbers. We match a SIP trunk to your call patterns and plan the porting of your numbers.
- Build and devices. We configure extensions, menus, queues, recording and integrations, provision desk phones and roll out the apps, much of it remotely.
- Go-live and changes. We test call flows with you, train users and supervisors, and can help with changes and renewals afterwards.
Forever Group's main site also covers 3CX support. Contact us with your user count and sites, and ask us for a quote.
How Forever Systems helps you choose a VoIP phone system
We supply and support several VoIP platforms, so we can recommend the one that fits how your team takes calls rather than fitting your business around one product.
- Platform advice across hosted 3CX, Microsoft Teams Phone, Webex Calling, Forever UC and Forever Teams, with SIP trunks for phone systems you already own
- A requirements check of your broadband, network and routers before anything goes live
- Numbers and porting: we can help you keep your existing business numbers and plan the move away from analogue and ISDN lines
- Handsets and headsets that suit each platform, bought outright or, in some cases, included in your monthly rental, with the options confirmed at quote
- Set-up and changes: call flows, users and devices configured for you, and help with moves, adds and changes afterwards
- For BT Cloud Voice, see our sister site cloudvoice.cloud, and for hosted and cloud platforms in depth, cloudphone.cloud
We work with businesses, schools, charities and public sector organisations.
Frequently asked questions
Is 3CX a VoIP phone system?
Yes. 3CX is a software IP PBX based on SIP. It gives users extensions, menus, ring groups, queues, voicemail and apps, and connects to the phone network through a SIP trunk. It can be hosted by 3CX, self-hosted in a cloud account or run on-premise.
Is 3CX free?
3CX SMB Free is free for up to 10 users and is hosted by 3CX. The commercial editions, Basic, PRO and AI, need an annual system licence sized by simultaneous calls, plus a SIP trunk and any desk phones. Ask us for a quote.
Which VoIP providers work with 3CX?
3CX publishes a directory of SIP trunk providers by country, including the United Kingdom, marked as 3CX Tested or VoIP Provider Tested, with pre-configured templates in 3CX. We help you choose a trunk that suits your call patterns and numbers.
Can I run 3CX on my own server?
Yes. 3CX can run on-premise on a Windows or Linux server or a supported virtual platform, or be self-hosted in your own Amazon, Azure, Google or DigitalOcean account. Hosted by 3CX is the option with no server to look after.
Is 3CX licensed per user?
No. 3CX commercial editions use one annual licence per system, priced by edition and simultaneous-call size. Each size has recommended and maximum user or extension limits, so the licence still has to fit the size of your system.
Which phones work with 3CX?
3CX publishes supported lists of IP desk phones, including Fanvil, Snom and Yealink, plus DECT systems, door phones and analogue adapters, many of which it provisions automatically. Users can also work from the web client and the Windows, iOS and Android apps.
Still have a question about 3CX?
Ask us and a member of our team will reply by email.
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