How do you calculate privileged account review load?

Divide the number of privileged OT accounts by your review rate to get base hours, then multiply by one plus the remediation allowance. With 360 accounts at 32 accounts/hr and a 40% allowance, base time is 11.25 hr and required time is 15.75 hr.

What is a good privileged account review rate?

For straightforward enumeration and access verification, 25-40 accounts per hour is realistic. Drop below that when accounts require deep cross-referencing against engineering roles, jump-host logs, or vendor contracts.

Why add a remediation allowance instead of just counting review time?

The review surfaces problems; the allowance covers fixing them. Disabling stale accounts, contacting owners, rotating shared HMI passwords, and documenting exceptions routinely add 30-50% on top of the inspection itself.

How often should privileged OT accounts be reviewed?

IEC 62443 and most OT security programs recommend recertifying privileged and remote-access accounts at least quarterly, with vendor and emergency accounts checked more frequently or after every use.

What allowance percentage should I use?

Start at 40% if you have decent identity hygiene and responsive owners. Push toward 60-80% for environments with shared credentials, many third-party vendors, or no prior baseline review.

Does this include time to actually remove accounts?

Partially. The allowance is meant to cover light follow-up and remediation. Large-scale deprovisioning, MFA rollout, or PAM onboarding should be scoped as separate projects, not folded into the review load.

Industrial Cybersecurity & OT Risk calculator

Privileged Account Review Load Calculator

Privileged Account Review Load estimates how many labor hours a periodic privileged access review of your OT environment will actually consume once you account for follow-up and remediation. OT and ICS security leads, IAM administrators, and IEC 62443 compliance owners use it to right-size quarterly or annual access recertification campaigns. It matters because privileged account reviews on plant networks are notoriously underscoped: the raw enumeration is fast, but chasing orphaned engineering-workstation logins, vendor remote-access accounts, and shared HMI credentials with their owners is where the time goes. Putting a defensible hour figure on the work helps you staff the campaign and avoid blowing through a maintenance window.

What this calculator does

Estimate labor hours to review privileged OT accounts, shared accounts, vendor accounts, and administrator access.
Use it when planning access recertification, audit evidence, and account cleanup for OT systems.
It computes base review hours as accounts divided by review rate, then multiplies by an allowance factor to add owner follow-up and remediation time.

Formula used

Base privileged account review time = privileged OT accounts to review ÷ privileged account review rate
Required privileged account review time = base privileged account review time × allowance factor

Inputs explained

Privileged OT accounts to review:
Privileged account review rate:
Owner follow up and remediation allowance:

How to use the result

Use it when planning a privileged access recertification cycle for OT/ICS assets or scoping a third-party access audit before a security window.
It assumes a steady per-account review pace; deeply nested service accounts, shared credentials, or unresponsive asset owners can blow past a flat percentage allowance.

Common questions

How do you calculate privileged account review load? Divide the number of privileged OT accounts by your review rate to get base hours, then multiply by one plus the remediation allowance. With 360 accounts at 32 accounts/hr and a 40% allowance, base time is 11.25 hr and required time is 15.75 hr.
What is a good privileged account review rate? For straightforward enumeration and access verification, 25-40 accounts per hour is realistic. Drop below that when accounts require deep cross-referencing against engineering roles, jump-host logs, or vendor contracts.
Why add a remediation allowance instead of just counting review time? The review surfaces problems; the allowance covers fixing them. Disabling stale accounts, contacting owners, rotating shared HMI passwords, and documenting exceptions routinely add 30-50% on top of the inspection itself.
How often should privileged OT accounts be reviewed? IEC 62443 and most OT security programs recommend recertifying privileged and remote-access accounts at least quarterly, with vendor and emergency accounts checked more frequently or after every use.
What allowance percentage should I use? Start at 40% if you have decent identity hygiene and responsive owners. Push toward 60-80% for environments with shared credentials, many third-party vendors, or no prior baseline review.

Last reviewed 2026-05-12.