Incident Severity Calculator
Classify a network incident from users affected, service degradation, duration and business criticality into a P1–P4 priority.
Inputs
100% means fully down, 40% means noticeably degraded.
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
Values used
Users affected = 2,500 users; Total users = 20,000 users; Service degradation = 100 %; Duration so far = 45 minutes; Business criticality of the affected service = Business critical
Incident Severity
severity = weighted impact × 0.5 + duration score (25) + criticality score (25), where weighted impact = reach × degradation.
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
How it works
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
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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