Scores your environment against Webex Calling and on-prem CUCM across user size, topology, features, compliance, and IT capacity. Returns a recommendation, confidence score, and migration path.
Cisco sells both Webex Calling and CUCM. Most "fit" calculators push you to cloud because that's where the commissions are. This one looks at six dimensions — size, topology, features needed, compliance, IT capacity, and sunk cost — and tells you the truthful answer, including "stay on CUCM for now, move in 3 years."
Fill inputs, click Run Fit Check.
Sweet spot: 100-5000 users.
Multi-site favors cloud.
Deep on-prem customization favors CUCM.
Strict sovereignty favors on-prem.
Lean teams favor cloud.
New CUCM/phones favor staying.
Each factor contributes a score (0-10) toward Webex Calling and toward CUCM, weighted by its importance. Size: under 100 users → cloud wins easily; 100-5000 → either works; 5000+ → CUCM still scales better per seat but cloud is closing the gap. Topology: multi-site favors cloud because you avoid CUCM-per-cluster overhead. Single site is neutral. Features: UCCX/CCE integrations, paging with Singlewire, heavy Phone Services XML customization, and specific G.729 corner cases favor staying on CUCM. Webex Calling contact center is now strong (Webex Contact Center) but the CUCM-side investment may be what drives this. Compliance: HIPAA works on both; SOX works on both; EU data sovereignty tilts toward on-prem or EU-region Webex; classified/DoD almost always requires on-prem.
IT capacity is the often-overlooked factor. Running CUCM requires ongoing patching, upgrades, backups, and DR. If you have 1 voice admin at 20% of their time, you're already behind on CUCM. Cloud removes that burden. Sunk cost is about existing investment: if you just bought 300 new 88xx phones or a fresh CUCM 15 cluster in the last 18 months, don't throw it away. Run it for the depreciation period, then migrate. If your CUCM is 12.5 (EoL 2026) or your phones are 79xx, migration pays back fast.
The output includes a confidence score. If both platforms score within 5 points, we say "either works, pick based on preference." If the gap is 15+, we strongly recommend the winner. Confidence also shows which factor is doing the most work — if the answer rests on one big factor, verify that factor before committing.
Depends on size + term. Often cheaper for under 500 users; closer to even at 1000+ over a 5-year TCO.
Yes, via CUCM-to-Webex Calling integration. Common transitional state.
78xx, 88xx, and DX work. 79xx requires replacement.
Option for orgs that want CUCM features but not the ops burden. Higher cost than Webex Calling Multi-Tenant.
CUCM hitting EoL, 79xx phones aging.
Healthy environment.
Heavy clinical integrations.
Our UC Health Assessment evaluates your environment end-to-end and recommends the platform that actually fits — not the one with the highest Cisco commission.