EC2 Health Score Calculator

score = 0.20 × CPU balance + 0.15 × memory balance + 0.15 × I/O + 0.25 × availability + 0.15 × patch currency + 0.10 × backup coverage. Utilisation is scored as distance from a target band rather than as more-is-better, because 5% CPU is a waste problem and 95% is a latency problem. Availability carries the heaviest weight since a failed status check is a real customer-visible event, and patch age is forgiven for the first 30 days to match a typical monthly maintenance cycle. The weakest sub-score is surfaced separately so the composite never hides a single critical failure behind five healthy dimensions.

A single score makes fleet-wide comparison possible, but remediation always starts from the weakest dimension — a 78 caused by missing backups is far more urgent than a 78 caused by low CPU.

This calculator takes 6 inputs: Average CPU utilisation, Average memory utilisation, Average disk queue depth, Failed status checks per month, Days since last patch, Backup and snapshot coverage. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

No, they are a sensible default for a general-purpose fleet, not an AWS standard. If your workload is latency-critical, raise the availability and I/O weights; if it handles regulated data, backup coverage and patch currency deserve more. What matters is applying the same weights consistently across the fleet.