The best small business PBX depends on one question: do you want to own a phone system or subscribe to one? Subscribe → a cloud PBX (flat per-seat, zero administration). Own → a software PBX like 3CX, FreePBX, or Yeastar on carrier SIP trunks (cheaper per user at scale, needs a competent admin). Everything else — vendor names, prices, features — hangs off that fork.
The r/sysadmin thread you probably just left says the same thing with more profanity. SIPNEX is an FCC-licensed carrier that serves both answers — our own cloud PBX, and trunks for the PBX you run — so this guide sorts by scenario instead of by affiliate payout.
First, the fork
Subscribe (cloud PBX) when: under ~25 phones, nobody wants to touch a dial plan, and predictable per-seat billing beats per-user math. All maintenance, upgrades, and carrier plumbing are the provider’s problem.
Own (IP PBX + SIP trunks) when: you have (or are) a capable admin, seat counts make per-user fees sting, or the routing itself matters — queues, custom IVR trees, integrations, any hint of outbound campaigns. Per-user cost drops as you scale; control is total; the trunk underneath is a separate, swappable decision.
Best by scenario
Office of 5–25, no IT appetite → carrier-direct cloud PBX. Flat per-extension pricing with every feature included avoids the tier ladder entirely. SIPNEX’s cloud PBX is this category (bias disclosed): recording, auto-attendant, ring groups included, no contract, A-level attestation on every call.
Meetings-first team that also calls → a UCaaS platform. If Zoom or Teams is the actual workspace, a bundled seat is pragmatic — Zoom Phone adds calling to Zoom from $10–15/user/month (metered vs unlimited, annual billing, July 2026). Just price the tier with the features you need: entry tiers across RingCentral ($20), Nextiva ($15 promo w/ 12-month term), Dialpad ($15), and Ooma ($19.95, month-to-month) gate recording, integrations, or SMS in different places — the pricing anatomy covers the gotchas.
10–100 seats with an admin → 3CX or Yeastar on SIP trunks. Commercial software PBXes with polished GUIs. Note 3CX’s V20 licensing: custom carrier trunks require the PRO/ENT tier — our 3CX setup guide covers it. Yeastar’s P-Series is the appliance-shaped alternative (setup guide).
Technical team, zero license budget → FreePBX/Asterisk or FusionPBX. Open-source, infinitely capable, honest about requiring skill. Want FreePBX without running the box? SIPNEX offers hosted FreePBX with trunks included. Tested configs: Asterisk/FreePBX, FusionPBX. Torn between the commercial and open-source forks? 3CX vs FreePBX runs the head-to-head.
Any outbound campaign volume → stop reading buyer’s guides for office PBXes. Dialer workloads are a different animal: dialer-grade trunking with VICIdial-class tooling.
The feature checklist that actually matters
Judge any small business PBX — cloud or owned — on these, not the 90-item marketing grid: auto-attendant and ring groups (the actual daily workflow); call recording at the price shown (the most commonly tier-gated feature); mobile/softphone parity; SMS on your business numbers (A2P-registered, with real caps disclosed); number portability in both directions; month-13 pricing without the promo; and who signs your calls — A-level vs B-level attestation decides how your caller ID is trusted.
Frequently asked questions
What is the best PBX for a small business?
For most offices under ~25 people: a cloud PBX with flat all-features pricing — no hardware, no admin, predictable per-extension cost. For teams with a capable admin or 25+ seats: 3CX, Yeastar, or FreePBX on carrier SIP trunks costs less per user and gives total routing control. The fork is ownership appetite, not vendor brand.
How much does a small business PBX cost?
Cloud: advertised entry seats run $10–$20/user/month (July 2026, annual billing) with real-world all-in costs above that once tiers and fees land. Owned: software licensing (from $0 for FreePBX/FusionPBX), modest server or appliance cost, plus SIP trunk usage at carrier rates — typically the cheaper path beyond a couple dozen users.
Do small businesses still need a PBX at all?
If more than one person answers calls, yes — a PBX (cloud or owned) is what provides extensions, an auto-attendant, ring groups, and voicemail routing. What small businesses no longer need is PBX hardware in a closet; the function moved to the cloud or to software.
Can I switch from a cloud PBX to my own PBX later?
Yes, and the migration is mostly number porting plus rebuilding routing on the new system. Keeping both layers with one carrier makes it easier still — SIPNEX customers move between cloud PBX seats and raw SIP trunks on the same numbers, same attestation, no porting event at all.
SIPNEX is an FCC-licensed carrier on both sides of the fork: cloud PBX with everything included, or SIP trunks for the PBX you own — A-level STIR/SHAKEN either way. Talk to an operator or see rates.
Keep reading.
The carrier built by operators, for operators.
FCC-licensed carrier with its own STIR/SHAKEN SP certificate. Operator-owned. SIP trunks built for operators who dial at volume.