Industrial Cybersecurity & OT Risk calculator
OT Asset Inventory Coverage Calculator
Use this calculator to measure how complete an OT asset inventory is. It helps teams track visibility before vulnerability management, backup planning, segmentation, monitoring, and compliance work.
What this calculator does
- Calculate OT asset inventory coverage using discovered assets, expected assets, and target coverage.
- Use it when measuring asset visibility for PLCs, HMIs, SCADA nodes, network devices, servers, and engineering workstations.
- The result shows asset inventory coverage and the point gap to target.
Formula used
- OT asset inventory coverage = OT assets inventoried ÷ expected OT assets in scope × 100
- OT asset inventory coverage gap to target = OT asset inventory coverage - target asset inventory coverage
Inputs explained
- OT assets inventoried: Count assets with owner, location, type, firmware or software detail, network zone, and criticality recorded.
- Expected OT assets in scope: Use the best known population from network discovery, control drawings, CMMS, engineering lists, vendor records, or site walkdowns.
- Target asset inventory coverage: Enter the coverage target from policy, audit plan, IEC 62443 program, or risk management standard.
How to use the result
- Use it to prioritize discovery, owner assignment, network zoning, and criticality classification.
- It depends on the expected asset population and does not prove that all details are accurate.
Common questions
- What is the OT asset inventory coverage calculator for? It calculates how much of the expected OT asset population is recorded in inventory.
- What information should I enter? Use inventoried asset count, expected asset count, and target coverage.
- What does the result tell me? The result helps plan discovery work and support patching, backup, and monitoring programs.
- When is the result only an estimate? It is only an estimate when asset sources disagree or unmanaged devices are not visible.
Last reviewed 2026-05-12.