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Azure RBAC Calculator

Track Azure role assignments against the 4000-per-subscription limit and custom roles against 500 per tenant.

About Azure RBAC Calculator

Azure counts each role assignment object against a per-subscription limit, and that limit is reached surprisingly often because assignments are made at resource-group and resource scope as well as subscription scope. Targeting a group instead of a user collapses many assignments into one without changing effective access. When a subscription hits 4000 assignments, new access requests simply fail, and the fix — re-modelling hundreds of user assignments onto groups — is a project rather than a ticket.

Formulas

Azure RBAC

utilisation = role assignments ÷ 4000 per subscription; a group assignment replaces one assignment per member, so savings = assignments × (members per group − 1).

500
Custom role definitions per tenant
4000
Role assignments allowed per Azure subscription
members
Users behind a single group assignment

Tenant-wide assignment footprint

assignments across the tenant = assignments per subscription × subscriptions.

subscriptions
Each carries its own independent 4000-assignment budget

Worked example

With the default values below, Azure RBAC Calculator returns Subscription Assignment Utilisation of 65.0%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Role assignments in the subscriptionaccepts 0–6,000 assignments
2,600 assignments
Custom roles in the tenantaccepts 0–1,000 roles
180 roles
Subscriptions in the tenantaccepts 1–1,000 subscriptions
6 subscriptions
Assignments target groups rather than users
Yes
Average members per groupaccepts 1–10,000 users
40 users

Results

Subscription Assignment Utilisation
65.0%
Assignments Remaining
1,400 of 4000
Custom Roles vs 500 per Tenant
36.0%
Assignments if Made per User
104,000
Assignments Saved by Group Targeting
101,400
Assignments Across All Subscriptions
15,600
Assessment
Within Azure RBAC limits

Step by step

  1. 1Values used
  2. 2Azure RBAC
  3. 3Tenant-wide assignment footprint
  4. 4Subscription Assignment Utilisation= 65.0
  5. 5Assignments Remaining= 1,400 of 4000
  6. 6Custom Roles vs 500 per Tenant= 36.0
  7. 7Assignments if Made per User= 104,000
  8. 8Assignments Saved by Group Targeting= 101,400
  9. 9Assignments Across All Subscriptions= 15,600

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Azure RBAC calculated?

utilisation = role assignments ÷ 4000 per subscription; a group assignment replaces one assignment per member, so savings = assignments × (members per group − 1). Azure counts each role assignment object against a per-subscription limit, and that limit is reached surprisingly often because assignments are made at resource-group and resource scope as well as subscription scope. Targeting a group instead of a user collapses many assignments into one without changing effective access.

Why does Azure RBAC matter?

When a subscription hits 4000 assignments, new access requests simply fail, and the fix — re-modelling hundreds of user assignments onto groups — is a project rather than a ticket.

What values do I need to enter?

This calculator takes 5 inputs: Role assignments in the subscription, Custom roles in the tenant, Subscriptions in the tenant, Assignments target groups rather than users, Average members per group. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

How do I stay under the Azure role assignment limit?

Assign roles to Microsoft Entra groups instead of individual users, prefer assignments at management-group or subscription scope over dozens of resource-scope assignments, remove assignments for deleted principals, and use Privileged Identity Management for eligible rather than permanent access so short-lived assignments do not accumulate.

Do inherited assignments count against the subscription limit?

No. An assignment created at management-group scope is counted against that management group, not against every subscription beneath it — which is exactly why moving broad access up the hierarchy is the fastest way to reclaim subscription headroom.

Azure RBAC Calculator | Calcrivo