Terraform Infrastructure Score Calculator

Score overall Terraform infrastructure health from drift, plan success rate, apply time and module reuse.

Inputs

Infrastructure Drift%

Percent of resources currently drifted from state.

Plan/Apply Success Rate%

Percent of plan/apply runs that complete without error.

Avg Apply Timeminutes

Average time for a `terraform apply` to complete.

Module Reuse%

Percent of resources provisioned via shared/reusable modules vs. one-off inline resources.

Infrastructure Score

82.7/100

Grade

Good

Drift Score

88/100

Plan Success Score

92/100

Apply Time Score

83/100

Module Reuse Score

65/100

Step by step

Drift score (30%)
100 - 6 × 2
= 88
Plan success score (30%)
92
= 92
Apply time score (15%)
100 - (6 - 1) / 29 × 100
= 83
Module reuse score (25%)
65
= 65
Weighted infrastructure score
0.3D + 0.3S + 0.15A + 0.25R
= 82.7

How it works

Infrastructure score blends four weighted signals: drift (30%, penalizing resources that diverge from state), plan/apply success rate (30%, reliability of the core workflow), apply time (15%, operational efficiency), and module reuse (25%, a proxy for consistency and maintainability). Each is normalized to 0-100 before weighting, mirroring the structure of the Git repository health score for a comparable DevOps maturity view.

Formula

score = drift_score × 0.30 + success_score × 0.30 + apply_time_score × 0.15 + reuse_score × 0.25

drift_score: clamp(100 - drift_percent × 2, 0, 100)
success_score: Plan/apply success rate percentage
apply_time_score: clamp(100 - (avg_apply_min - 1) / 29 × 100, 0, 100)
reuse_score: Module reuse percentage

Frequently Asked Questions

Why do drift and success rate carry equal, highest weight?

Both directly reflect whether your infrastructure-as-code can be trusted as the source of truth — high drift means your code lies about reality, and low success rate means the core workflow (plan/apply) itself is unreliable, undermining confidence in every other metric.

How is module reuse measured in practice?

Divide resources provisioned through calls to shared/versioned modules by total managed resources — a high ratio indicates standardized, DRY infrastructure patterns rather than repeated inline resource blocks per environment.

Can a fast-applying configuration still score poorly overall?

Yes — apply time only carries 15% weight, so a fast but heavily drifted or unreliable (low success rate) configuration will still score low overall, correctly reflecting that speed doesn't offset trustworthiness issues.

How should I act on a low infrastructure score?

Start with whichever sub-score is lowest: schedule drift remediation if drift is high, investigate flaky providers/modules if success rate is low, or invest in a shared module library if reuse is low.

You might also need

Terraform Drift Calculator Terraform Plan Complexity Calculator Git Repository Health Score Calculator