Has anyone done a quantifiable ROI analysis for ZTNA?

You're right, the VPN cost piece can be a wash if you just swap line items. The real difference for us was operational overhead. We saw about a 40% reduction in Tier 1 help desk tickets related to client issues, connection drops, and profile corruption. That's measurable support time and user frustration saved right there.

On the productivity side, it's tough. We didn't try to quantify speed gains in seconds. Instead, we surveyed our hybrid teams about "friction to start working." The score improvement after ZTNA rollout was significant, and we tied that to fewer interruptions and project delays. It's softer, but it convinced our finance folks when combined with the hard ticket reduction.

You're hitting on the exact challenge I see a lot. Building a purely financial model is tricky because so much of the value is on the operational and risk-reduction side.

For your productivity white whale, I'd suggest looking at it as a reduction in lost work blocks, not speed gains. We tracked the average time to resolution for "I can't get to my app" tickets before and after. The time spent by both the user and IT dropped dramatically because the access model is so much simpler. That's quantifiable work-hours saved.

On the VPN cost, modeling it as just a license swap misses the point. The real saving for us was retiring an entire legacy authentication server and its maintenance overhead. The ZTNA service absorbed that function. So look at the *entire* supporting infrastructure you can decommission, not just the VPN concentrator itself.

Great question on the VPN cost modeling. We moved away from a direct cost swap mindset and focused on workload shift. The big one for us was offloading authentication logic.

Our old VPN relied on an on-prem RADIUS server. Managing that, plus the constant patching for the VPN gateway itself, was easily 15-20 hours a month for a network engineer. The ZTNA service handles all the auth and we just feed it an identity provider. That engineer time was reallocated to actual project work.

On the productivity side, you mentioned the connection speed theory. We saw a clearer signal in app-specific timeouts. With the VPN, certain database tools would constantly stall. We logged those 'waiting' events before and after. The drop wasn't huge per user, but multiplied across the team it added up to a real number of recovered hours each week.

You're right that the direct license swap often looks like a wash. The productivity piece is where we found measurable, if indirect, numbers.

For the "friction to start working" idea, we tracked session-initialization failures. With the VPN, about 8% of daily sessions required a reconnect or help desk ticket. That's pure lost time. With ZTNA, that dropped to under 1%. You can translate that percentage into average salary cost for the time-to-resolution. It's not about faster connections, it's about reliable ones.

On infrastructure, don't just look at the VPN hardware. Account for the reduced load on your network edge firewalls. With app-specific access, you can drastically cut down on the volume of "any-any" traffic you're inspecting, which deferred a hardware refresh for us. That's a capital cost avoided.

Your point about the net savings being a direct cost swap is where most models fail. We shifted our calculation from "license vs. license" to "total cost of the access stack."

For us, the ZTNA subscription wasn't just a VPN replacement. It let us consolidate and sunset three other services: a basic SASE proxy, a legacy web portal, and a niche MFA gateway for contractors. That's three fewer vendors to manage, renew, and monitor. The net saving was positive when we added those avoided costs back in.

On productivity, measuring the lack of interruption was key. We audited Slack channels for phrases like "vpn down" and "can't connect" for a month pre and post rollout. The volume drop was stark, and we estimated the lost minutes per incident. It's not about speed, it's about not stopping at all.

> How are you modeling the *net* savings when switching from a mature VPN setup to a subscription ZTNA service?

We had to broaden the scope beyond the license line item to make the math work. The big win was consolidating point solutions. Our ZTNA provider had built-in secure web gateway capabilities that were "good enough" to retire a separate cloud proxy subscription. That alone covered 60% of the ZTNA cost right there.

For productivity, we gave up on measuring connection speed. Instead, we tracked "access failure events" that triggered a support ticket or a team chat complaint. With the VPN, we had about 12 of those daily across 300 users. Post-ZTNA, it's maybe 2. We estimated each event burned 15 minutes of user time and 20 minutes of IT time. That hourly cost adds up fast and gave us a clean, monthly productivity savings figure.

Yeah, the ticket reduction is huge. We mapped our VPN support cost as an hourly rate for the help desk plus the blended cost of the user being blocked. That "user frustration" you mentioned actually has a price tag.

> We surveyed our hybrid teams about "friction to start working."

We did something similar, but used an engineering team's sprint data. They had fewer "blocked" tickets post-ZTNA because devs weren't waiting on VPN fixes to reach internal tools. That shift showed up in their velocity, which got the product team's attention.

Love that you pulled sprint velocity data. That's a brilliant, tangible angle for the productivity case that moves beyond speculative speed tests.

But I'm curious - did you isolate the ZTNA impact from other variables? For instance, if the engineering team also adopted a new CI/CD tool or had a quiet period on infrastructure changes around the same time, the velocity bump could be conflated. How did you control for that, or did you just present the correlation and let the timing of the rollout speak for itself?

The product team caring about dev velocity is a way stronger lever than generic "user happiness" surveys.

Totally get the struggle with the productivity numbers. We looked at it as a reduction in context switching, not just speed.

For the VPN cost swap, it's rarely a 1:1. You have to factor in what you're decommissioning. In our case, moving to ZTNA meant we could simplify our AWS network ACLs and VPC routing, which directly cut our NAT Gateway data processing costs by about 30%. That was a tangible line item.

On the white whale of user experience, we found the best proxy was tracking abandoned tasks in our internal admin portals. With VPN timeouts, users would just give up and try again later. Post-ZTNA, that drop-off rate vanished. It's hard to put a dollar figure on a single event, but tracking the trend monthly showed a clear reduction in incomplete workflows.

I completely agree on looking beyond the license cost. Your point about simplifying VPC routing to reduce NAT Gateway costs is a concrete example we found as well, though the savings were in egress fees for us.

>The best proxy was tracking abandoned tasks in our internal admin portals.

We measured this indirectly via application log analytics. By creating a metric for "session duration under 60 seconds with no successful transaction" on key internal tools, we established a baseline pre-migration. Post-ZTNA, that metric fell by about 22%. It's still a proxy, but it's tied directly to system data, not user surveys, which made the finance team take it more seriously.

The harder correlation is proving those incomplete workflows would have resulted in a later support ticket or a delayed business process. We had to use historical ticketing data to assign a probability cost.

You're right to focus on the net savings rather than a simple license swap. In our analysis, the "VPN cost reduction" line item was only a small part of the total value. The larger financial impact came from decommissioning adjacent infrastructure.

For example, implementing ZTNA allowed us to significantly reduce the number of public IPs and firewall rules required for external access. This directly lowered our cloud provider's network security group and firewall costs. These are measurable, recurring monthly charges that dropped immediately post-migration.

On the user experience side, we found tracking "escalated access events" more reliable than modeling theoretical speed gains. Every ticket that moved from the helpdesk to a network engineer for a VPN tunnel issue carried a much higher blended labor cost. The reduction in those Level 2 escalations provided a clear, defensible hourly savings we could present.

>escalated access events

That's the right unit of work to measure. The blended cost of a L2 network engineer troubleshooting a site-to-site VPN tunnel versus a help desk agent resetting a ZTNA client is massive.

We also tracked the MTTR difference. A ZTNA identity or policy misconfiguration is usually resolved in minutes. A dead VPN tunnel often meant a multi-hour packet capture and vendor call. You can quantify that as a direct risk reduction in incident blast radius.

You're trying to quantify a productivity gain that's mostly speculative. What if the 'faster connection' doesn't translate to more work done, just more time spent on social media?

Your real cost is the subscription trap. You'll tally the old VPN hardware depreciation, but will you forecast the 20% annual price hikes for the ZTNA service after year three? The ROI vanishes when you're locked in.

You're stuck because you're looking for a singular metric. The ROI is in the aggregation of micro-efficiencies across disparate systems.

For the VPN cost swap, don't model it as "VPN vs ZTNA license". Model it as "cost of the access control *system*". The VPN is just one component. Our analysis found the real net saving came from the subsequent simplification of our cloud network topology, which reduced VPC peering data transfer costs and allowed us to downsize NAT gateway instances. These were line items in a different budget.

On productivity, abandon speed tests. They're noise. Instead, instrument your internal tooling. We added a simple log event for "access_start" to "first_meaningful_action" on our critical admin portals. The 90th percentile latency for that sequence dropped from ~45 seconds (VPN tunnel + DNS + internal routing) to under 8 seconds post-ZTNA. Multiply that reduction by the daily number of access events and an average loaded salary cost. It's not perfect, but it's a defensible, data-driven proxy for lost time.