SIP Trunking vs Hosted VoIP
Every business replacing phone service reaches this fork. The honest answer: hosted VoIP (UCaaS) is right for most businesses, SIP trunking is right for a specific minority — and knowing which you’re in saves thousands.
The one-sentence difference
SIP trunking delivers dial tone over the internet to the phone system you already own; hosted VoIP moves the phone system itself to the provider’s cloud, and you just attach phones and apps.
Side by side
| Factor | SIP trunking | Hosted VoIP (UCaaS) |
|---|---|---|
| Keep existing PBX | ✅ Yes — that’s the point | ❌ Replaced |
| Upfront cost | Low (keep hardware) | Phones only (or BYOD) |
| Ongoing cost | Per concurrent channel ($10–25) | Per user ($15–45, features included) |
| New features | Limited by your PBX’s age | Auto-shipped (AI, transcriptions, apps) |
| Mobile/remote apps | Rarely included | Standard |
| Maintenance | Your PBX, your problem | Provider’s problem |
| Control/compliance | Max (on-prem recording, routing) | Provider-configured |
| Failure mode | Trunks fail → PBX fails | Provider handles resiliency |
Choose SIP trunking when…
- Your PBX is healthy (or recently invested) and you only want cheaper, scalable dial tone.
- You have specialized on-prem integrations (legacy apps, overhead paging, compliance-driven local recording) that a cloud swap would break.
- Your usage profile is channel-efficient — high call concurrency relative to headcount (call centers with SIP can be very cost-effective).
- You’re staged-migrating: trunks now, hosted later, without a cliff.
The providers we quote most for trunks: Sangoma (own hardware + FreePBX ecosystem), TPx (fully managed), AireSpring (value, multi-site).
Choose hosted VoIP when…
- The PBX is aging, end-of-life, or unsupported (the most common situation — don’t sink money into yesterday’s platform).
- You want mobile apps, chat, video and modern features included.
- IT headcount is thin — hosted moves maintenance to the provider.
- You’re adding remote/hybrid workers — hosted handles them natively.
Start with the UCaaS rankings and hosted PBX picks.
The math that decides it
Model three years, both ways, including: PBX maintenance and end-of-life refresh (SIP path) vs per-user licensing with zero hardware (hosted path). For a 25-user office with a 10-year-old PBX, hosted typically wins by year two. For a 200-user call center with a invested platform, SIP trunks often win for years.
Want both modeled on your real numbers? We quote both paths free — it’s a 30-minute exercise that settles the debate with dollars.