How do you calculate network segmentation ROI?

Subtract annual segmentation support cost from annual risk-reduction savings to get net annual savings, then divide the project investment by that net figure. With $240,000 invested, $95,000 saved, and $26,000 support, net savings are $69,000 and payback is about 3.48 years.

What is a good payback period for OT segmentation?

In OT, anything under 3 years is generally strong because flat-network incidents can halt production. The 3.48-year payback in the default example is reasonable for a plant-wide project; smaller, high-risk zones often pay back in under 18 months.

Why subtract support cost from the savings?

Segmentation is not set-and-forget. Firewall rule reviews, monitoring, and policy updates carry recurring labor and licensing. Netting the $26,000 support against the $95,000 savings gives the true annual benefit of $69,000.

How is this different from a generic IT firewall ROI?

OT segmentation protects physical process safety and uptime, so the avoided-loss side includes production downtime, safety incidents, and scrap, not just data breach cost. That usually pushes the dollar value of risk reduction higher per dollar invested.

What is the five-year net value in this calculator?

It is the cumulative net savings over five years minus the original investment: five years of $69,000 ($345,000) less the $240,000 project cost equals $105,000 of net value.

Should I include the cost of production downtime during cutover?

Yes — fold any planned outage cost into the project investment line so the payback reflects the real all-in cost, not just hardware and integration labor.

Industrial Cybersecurity & OT Risk calculator

Network Segmentation ROI Calculator

Network segmentation ROI tells an OT security or controls engineering team how long it takes for an industrial segmentation project — VLANs, firewalls, conduits, and zone/conduit architecture per IEC 62443 — to pay for itself through reduced cyber risk. It compares the up-front capital to deploy segmentation against the annual loss it prevents, net of the cost to keep firewall rules, monitoring, and zone policies maintained. Plant managers, OT security leads, and CISOs use it to justify segmentation budget against competing capital projects. Because OT downtime from a flat network can run tens of thousands of dollars per hour, payback periods here are often shorter than IT teams expect.

What this calculator does

Estimate payback for OT network segmentation using project investment, annual risk reduction savings, and annual support cost.
Use it when evaluating zones, conduits, industrial firewalls, remote access separation, or plant network redesign.
It computes the payback period in years for an OT network segmentation project from the investment, annual risk-reduction savings, and annual support cost.

Formula used

Net annual segmentation savings = annual risk reduction savings - annual segmentation support cost
Network segmentation payback period = segmentation project investment ÷ net annual savings

Inputs explained

Segmentation project investment: Include design, industrial firewalls, switches, implementation labor, testing, downtime coordination, documentation, and training.
Annual risk reduction savings: Use expected savings from reduced downtime exposure, lower incident response cost, easier compliance, faster containment, or avoided production disruption.
Annual segmentation support cost: Include firewall administration, rule review, monitoring, spares, license renewals, change management, and support contracts.

How to use the result

Use it when scoping a segmentation initiative or defending the capital request to finance, before committing to firewall, switch, and architecture spend.
Annual risk-reduction savings is an estimate of avoided loss, not booked cash, so the payback is only as credible as your loss-event probability and impact modeling.

Common questions

How do you calculate network segmentation ROI? Subtract annual segmentation support cost from annual risk-reduction savings to get net annual savings, then divide the project investment by that net figure. With $240,000 invested, $95,000 saved, and $26,000 support, net savings are $69,000 and payback is about 3.48 years.
What is a good payback period for OT segmentation? In OT, anything under 3 years is generally strong because flat-network incidents can halt production. The 3.48-year payback in the default example is reasonable for a plant-wide project; smaller, high-risk zones often pay back in under 18 months.
Why subtract support cost from the savings? Segmentation is not set-and-forget. Firewall rule reviews, monitoring, and policy updates carry recurring labor and licensing. Netting the $26,000 support against the $95,000 savings gives the true annual benefit of $69,000.
How is this different from a generic IT firewall ROI? OT segmentation protects physical process safety and uptime, so the avoided-loss side includes production downtime, safety incidents, and scrap, not just data breach cost. That usually pushes the dollar value of risk reduction higher per dollar invested.
What is the five-year net value in this calculator? It is the cumulative net savings over five years minus the original investment: five years of $69,000 ($345,000) less the $240,000 project cost equals $105,000 of net value.

Last reviewed 2026-05-12.