Hosted PBX vs VoIP: The Difference Explained
Tom Reed · Updated 15 November 2026
VoIP is the technology that carries phone calls over the internet; a hosted PBX is a complete business phone system, with extensions, call routing and voicemail, that runs off-site and uses VoIP to make and take calls. So PBX vs VoIP isn't really either/or: when a business switches to VoIP, it is usually moving to a hosted PBX. SessionPBX is a multi-tenant PBX that partners can run on their own servers or have SessionTalk host.
This guide is for business buyers comparing the two terms, and for the MSPs, ITSPs, VoIP providers and IT resellers who get asked "VoIP or PBX?" by their customers. It explains each one in plain language, compares them side by side and helps you decide what you need.
What is the difference between hosted PBX and VoIP?
VoIP is the technology; a hosted PBX is the system. VoIP describes how voice calls travel, as data over the internet instead of over a traditional phone line. A hosted PBX is the business phone system that sits on top, handling extensions, transfers, ring groups and voicemail from a provider's servers instead of a box in your office.
Think of VoIP as the road and the hosted PBX as the delivery service that runs on it. You can have the road without the service, but a business that wants to manage many people and calls usually wants the service too.
What is VoIP?
VoIP, short for voice over internet protocol, sends calls as data over an internet connection. People make those calls from apps, desk phones or computers. VoIP on its own gives you calling, as long as you have a phone or app and a SIP account.
To reach outside numbers, VoIP needs a carrier, usually through a SIP trunk. For a deeper look at how a small business can use it, read our VoIP phone system for small business guide, and see whether VoIP is reliable for business before you switch.
What is a hosted PBX?
A hosted PBX is a business phone system that runs off-site. Instead of buying and maintaining a box in a cupboard, you use a system managed centrally, with extensions, call transfers, ring groups, voicemail and an auto-attendant, and your team calls from apps and phones. If you are asking what hosted PBX means, that is it: the phone system, delivered as a service.
People also say cloud PBX for the same idea; our post on hosted PBX vs cloud PBX covers the wording. To see what a PBX is at its core, read the PBX phone system guide.
PBX vs VoIP: how do they compare?
Here is the comparison at a glance. The VoIP column stays generic because VoIP is a technology, not a product.
| VoIP | Hosted PBX (e.g. SessionPBX) | |
|---|---|---|
| What it is | Technology: voice calls sent as data over the internet | A business phone system run off-site, using VoIP |
| What you get | Calling, given an app or phone and a SIP account | Extensions, transfers, ring groups, voicemail; on Teams Business also call flows, auto-attendant and IVR, queues, recording and reports |
| Where it runs | n/a, it is how calls travel | Provider's servers; with SessionPBX, the partner's own servers or SessionTalk hosting |
| Outside numbers | From a carrier or SIP trunk | Still from a SIP trunk: SessionPBX connects to any SIP-compliant carrier |
| Users' devices | Softphone apps, desk phones | SessionTalk softphones on Windows, macOS, iOS and Android |
| Management | Per line or account | Central portal for extensions, seats and permissions |
A related question is trunk versus PBX: a trunk connects you to the carrier, while the PBX runs the calls inside. Our post on SIP trunking vs cloud PBX explains it. Teams Phone and Teams Business are SessionPBX plan names, not Microsoft Teams.
Is PBX outdated?
The old on-site box is being replaced, but the PBX functions are not. Businesses still need extensions, transfers, routing, voicemail and a way to manage who can do what. A hosted PBX keeps those functions without on-site hardware to look after.
If you still run a box in the office, read how to migrate an on-premise PBX to a hosted PBX for the steps involved.
Which do you need: plain VoIP lines or a hosted PBX?
Use this short checklist to decide between VoIP vs PBX for your business.
- Only a handful of users who just need a number and calls? Plain VoIP lines may be enough.
- Need to transfer calls, use extensions or share a main number? Choose a hosted PBX.
- Need an auto-attendant, call queues, recording or reports? Choose a hosted PBX on a plan with those, such as SessionPBX Teams Business.
- Staff working from home or on mobiles? Choose a hosted PBX with the softphone apps your users call from.
- Already have a SIP trunk? Keep it and add the PBX on top.
- Want your IT provider to manage it? Ask your MSP whether it resells hosted PBX.
How do MSPs and ITSPs explain and resell this?
Customers often ask "VoIP or PBX?" and partners can answer "both": a SIP trunk from any SIP-compliant carrier plus SessionPBX seats. That keeps the carrier choice open and gives the customer a proper phone system on top.
For many partners the best fit is self-hosted multi-tenant SessionPBX on their own servers. Self-hosting is available to approved partners, uses annual licences and means the partner covers server, hosting and network costs. SessionTalk can also host it for you, in London, New York or Singapore. Partners can add their own logo and in-app name to the softphones with app logo branding.
To go deeper, read our guides to the hosted PBX reseller model and self-hosted PBX hosting for VoIP resellers, and see how UCaaS compares with hosted PBX for resellers. When you are ready, the SessionPBX Partner Programme explains how to apply.
FAQ
Is hosted PBX the same as VoIP?
No. A hosted PBX uses VoIP, but VoIP on its own is only the calling technology. Think of VoIP as how the call travels and the hosted PBX as the phone system that manages it, with extensions, routing and voicemail. Most hosted PBX systems rely on VoIP, so the two usually appear together.
Which is better, PBX or VoIP?
It is the wrong question, because they are not competing options. The real choice is between an on-site PBX and a hosted PBX, and both can use VoIP to carry calls. If you want a business phone system without on-site hardware, a hosted PBX is the usual fit.
Is PBX outdated?
The on-site box is fading, but PBX features are not. Businesses still need extensions, call transfers, ring groups and voicemail. A hosted PBX delivers those without hardware in your office, so the idea behind the PBX lives on while the cupboard full of equipment goes away.
Do I still need a SIP trunk with a hosted PBX?
Yes, for calls to outside numbers. SessionPBX includes internal calls between team members, and you connect a SIP trunk from any SIP-compliant carrier for everything else. Our guide to connecting a SIP trunk to a hosted PBX shows how the pieces fit together.
How much does hosted PBX cost?
It depends on the number of seats, the plan you choose and your carrier usage. We do not quote figures here; what costs extra with a hosted PBX explains what to look for. Partners who resell SessionPBX set their own price for their customers.
Is cloud PBX vs VoIP different from hosted PBX vs VoIP?
It is the same comparison. Cloud PBX and hosted PBX are close cousins: both describe a phone system run off-site that uses VoIP to carry calls. If you want to see how the two names differ, read hosted PBX vs cloud PBX for a plain-language comparison.
Want to offer this to your customers? Become a SessionPBX partner, or see SessionPBX features.
