3CX vs Zoom Phone — UK comparison, watch the metered tier

Zoom Phone tier breakdown.

Metered — £8.07/user/mo. Includes the Zoom Phone licence but NOT calling minutes. UK landline / mobile calls billed per-minute (currently ~£0.024 to UK landlines, ~£0.10 to UK mobiles at standard Zoom Phone metered rates). Easy to overspend if usage estimates are wrong.
Pro — £11.84/user/mo. Includes unlimited UK domestic calling. The realistic SME tier.
Pro Plus — £18.59/user/mo. Adds the Zoom Workplace suite and AI Companion features.

The Metered tier looks cheap on the headline. In practice, a UK SME with 25 users making ~30 minutes outbound to landlines and ~10 minutes to mobiles per user per day pays an extra ~£100–150/month over the Metered headline — roughly the difference between Metered and Pro. For most firms, Pro is the right pick.

Pricing comparison at 30 users.

Tier	Zoom Phone Pro	3CX (Port Phones managed)
Per-user / mo	Zoom£11.84	Port Phones~£8
Monthly (30 users)	Zoom£355 / mo	Port Phones~£240 / mo
24-month difference	~£2,750Smaller than the RingCentral/8x8 differential — Zoom Phone is genuinely competitively priced.

Where Zoom Phone wins.

Zoom Meetings integration. If your firm is heavily Zoom Meetings-centric for video, having calling in the same vendor is a coherent stack. Same login, same admin console, same support.
Cheap entry tier (Metered) for very-low-volume usage. A 5-user firm making 10 calls a week genuinely pays under £50/month on Metered. 3CX SMB FREE is also under £50/month (free, in fact) but requires DIY setup.
Polished UX. Zoom's product design is well-regarded. Calls in the Zoom client work the same way Zoom meetings do.
Global presence. Zoom Phone is in 47+ countries. UK-based firms with international footprint get coherent single-vendor coverage.

Where 3CX wins.

Better PBX features at standard tier. 3CX PRO includes advanced call queues with announced wait, callback-on-busy, supervisor wallboards, IVR designer, hot desking, switchboard. Zoom Phone Pro has basic queues; the more advanced PBX features require Pro Plus or aren't available.
UK partner relationship. Zoom Phone UK support is the global Zoom queue. 3CX through Port Phones is a direct UK MSP.
UK SIP via Gamma at competitive rates. Zoom Phone's "unlimited UK" sounds attractive but the underlying SIP is via Zoom's own carrier relationships. Gamma SIP through 3CX is well-understood, well-integrated, and competitive at usage-based rates.
Per-system pricing on growth. 30 users on Zoom Phone Pro costs £355/mo. 50 users costs £590. 100 users costs £1,180. Adding 10 more is always +£120/mo. 3CX scales by SC band, with much shallower growth slopes.

Who should pick which.

Pick Zoom Phone if: you're heavily invested in Zoom Meetings, you want a polished out-of-the-box UX, you're under 20 users with simple needs, or the Zoom brand simplifies procurement.
Pick managed 3CX if: you need PBX depth (queues, recording, IVR), you care about TCO above 30 users, or you want a UK partner relationship.
Pick Metered (carefully) if: you have genuinely-low call volume (under 5 min/user/day average) and want the cheapest viable option. Monitor the bill monthly.

What we'll tell you at audit.

Zoom Phone is the most-credible competitor in the SaaS PBX space on raw price. The honest answer for a 20–50 user firm at typical usage levels is a ~£100–200/month preference for 3CX-managed, plus the PBX feature depth. For very-Zoom-centric firms or very-small ones, Zoom Phone may genuinely be the right call. Book a free audit and we'll model both against your real call volume.

Book a free audit Already on Zoom Phone?