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Incident Severity Calculator

Classify a network incident from users affected, service degradation, duration and business criticality into a P1–P4 priority.

About Incident Severity Calculator

Reach alone over-states severity for partial degradation, so it is multiplied by the degradation factor before scoring. Duration is scored against a four-hour reference and business criticality contributes a fixed band, which keeps a small but revenue-critical outage from being classified as minor. Consistent severity scoring is what makes escalation predictable, and user-minutes lost is the figure that survives contact with a post-incident review.

Formula

Incident Severity

severity = weighted impact × 0.5 + duration score (25) + criticality score (25), where weighted impact = reach × degradation.

reach
Affected users as a percentage of the total
degradation
How badly the service is impaired, not just whether it is impaired

Worked example

With the default values below, Incident Severity Calculator returns Severity Score of 29.7. Change any input above and every figure here is recalculated in your browser.

Inputs used

Users affectedaccepts 0–100,000,000 users
2,500 users
Total usersaccepts 1–100,000,000 users
20,000 users
Service degradationaccepts 1–100 %
100 %
Duration so faraccepts 0–100,000 minutes
45 minutes
Business criticality of the affected serviceone of Revenue-generating or life-safety, Business critical, Business operational, Administrative
Business critical

Results

Severity Score
29.7 /100
Priority
P3 — Moderate
Weighted User Impact
12.50%
User-Minutes Lost
112,500
Escalation Required
Assign to the duty engineer with hourly updates

Step by step

  1. 1Values used
  2. 2Incident Severity
  3. 3Severity Score= 29.7 /100
  4. 4Priority= P3 — Moderate
  5. 5Weighted User Impact= 12.50
  6. 6User-Minutes Lost= 112,500
  7. 7Escalation Required= Assign to the duty engineer with hourly updates

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 2 decimal places, 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 Incident Severity calculated?

severity = weighted impact × 0.5 + duration score (25) + criticality score (25), where weighted impact = reach × degradation. Reach alone over-states severity for partial degradation, so it is multiplied by the degradation factor before scoring. Duration is scored against a four-hour reference and business criticality contributes a fixed band, which keeps a small but revenue-critical outage from being classified as minor.

Why does Incident Severity matter?

Consistent severity scoring is what makes escalation predictable, and user-minutes lost is the figure that survives contact with a post-incident review.

What values do I need to enter?

This calculator takes 5 inputs: Users affected, Total users, Service degradation, Duration so far, Business criticality of the affected service. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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