What is the difference between UCaaS and VoIP?

The comparison is awkward because "VoIP" names more than phone calls. The NIST glossary defines it as a group of technologies used to provide voice, video and collaboration communications over a data network using internet protocols. That definition is about how communication travels, and it reaches past voice. It says nothing about how many features a product has. We cover the mechanics in what VoIP is.

A buyer asking this question is comparing something narrower. On one side is a phone service delivered over the internet, with numbers, extensions and call routing. On the other is a UCaaS service, which puts meetings and team messaging beside that phone service in one set of apps.

The two blur at the edges. A company that calls itself a VoIP provider can sell chat and video, and a UCaaS provider's calling is VoIP. The label on the page doesn't settle what's inside.

VoIP also reaches places UCaaS doesn't. A business that keeps its own phone system in the office can connect it to the outside world over IP, and that's VoIP with no cloud suite involved. Atlantech Online's UCaaS page mentions this route. Its SIP trunking lets a business with an existing PBX add a softphone for its users without replacing the system yet. We separate those terms in the difference between SIP trunking and VoIP.

Atlantech's page shows how one hosted phone system can be sold at more than one scope. Its pricing section has two cards. The Business Line starts at $12 per user per month. Its card lists call handling features such as call forwarding, transfer, hunt groups and park and pickup, with unlimited local and domestic long-distance calling. The Premium Line starts at $18 per user per month. Its card lists voicemail, conferencing, collaboration and a softphone.

Both lines run on the phone system in Atlantech's cloud, and both carry voice as VoIP. What differs between the cards is the set of applications named around the call. That's the UCaaS and VoIP difference in practical form: the same calling technology, sold with more or fewer tools beside it.

Both figures are advertised starting rates. The quote sets the term, taxes and setup, and it confirms which features come with each line. Rates from other providers, with their own terms, are in how much UCaaS costs per user.

Calls among staff inside a collaboration suite are VoIP too, and that alone doesn't make the suite a business phone system.

Microsoft Teams shows why. Microsoft's Teams calling overview says calls between Teams users are handled by its cloud service, are unlimited, and are turned on by default for licensed users. Making and receiving outside telephone calls requires Teams Phone licensing for the user and a connection to the public telephone network for the organization. A company can use Teams for meetings, chat and calls among its staff before it has bought either one.

So a collaboration suite and a UCaaS service aren't automatically the same thing. The suite becomes a business phone system once the license and the carrier connection are added. We explain those pieces in what Microsoft Teams Phone is and whether a Teams Phone license includes a phone number.

Since the labels overlap, the useful comparison is between the applications you need and the ones you already have. Write down whether you need business calling with outside numbers, whether you need meetings, and whether you need team chat. Then mark which of those you already pay for somewhere else and plan to keep.

Suppose a 20-person office holds its meetings and chats in an office suite it has no plan to leave. What it's buying is calling, and a bundle would give it a second meeting tool nobody opens. Suppose also that Atlantech's quote confirms the Business Line covers the calling features this office needs. At the $12 starting rate, 20 users come to $240 a month before taxes and any other charges, if every user is on that line and the quote comes in at the starting rate.

Now suppose the same office pays for a phone service, a separate meeting tool and a separate chat tool, and people complain about switching between them. A UCaaS plan can replace all three with one set of apps. Suppose the quote confirms the Premium Line includes the meeting and messaging tools the office needs. At the $18 starting rate, 20 users come to $360 a month on the same assumptions.

The fair comparison is that figure against the total of the subscriptions the office would cancel, and an office on a phone-only service faces the same arithmetic when it decides when to switch from VoIP to UCaaS. If the office would keep one of those subscriptions anyway, it stays out of the savings.