What is commitment coverage rate?
Definition
Commitment coverage rate is the share of commitment-eligible spend actually covered by Savings Plans, Reserved Instances, or committed use discounts. It has a twin — utilization, the share of purchased commitment that gets used — and the two must be read together: low coverage wastes savings, low utilization wastes money.
Formula: Coverage rate = commitment-covered spend / commitment-eligible spend × 100
What data do you need?
- Billing line items with pricing model per line
- Eligibility flags — not all usage can be covered by commitments
- Commitment inventory with term, scope, and expiration dates
- Commitment purchased vs. used amounts for the utilization twin
- Amortized cost so upfront purchases spread correctly
SQL pattern
Coverage rate by service, last complete monthPostgreSQL
SELECT
service,
ROUND(SUM(cost_usd) FILTER (WHERE is_commitment_eligible), 2)
AS eligible_spend,
ROUND(SUM(cost_usd) FILTER (WHERE pricing_model IN
('SavingsPlan', 'Reserved')), 2) AS covered_spend,
ROUND(
100.0 * SUM(cost_usd) FILTER (WHERE pricing_model IN
('SavingsPlan', 'Reserved'))
/ NULLIF(SUM(cost_usd) FILTER (WHERE is_commitment_eligible), 0), 1
) AS coverage_pct
FROM billing_line_items
WHERE usage_date >= date_trunc('month', CURRENT_DATE) - INTERVAL '1 month'
AND usage_date < date_trunc('month', CURRENT_DATE)
GROUP BY service
ORDER BY eligible_spend DESC;Common pitfalls
Chasing 100% coverage.→ Committed capacity for workloads that shrink becomes waste; target steady-state load and leave volatile usage on demand.
Reporting coverage without utilization.→ Show both — high coverage with low utilization means over-commitment, which a coverage-only view celebrates.
Using total spend as the denominator.→ Divide by commitment-eligible spend; including ineligible services understates real coverage.
Where does this metric apply?
This metric commonly uses data from AWS Billing, Google Cloud Billing, Vantage, plus any warehouse models built on raw billing exports at the same grain.
Related
Dashboards
Integrations
Metrics
Analytics
FAQ
How far ahead should expirations be tracked?
90 days minimum. An expired commitment silently converts covered usage to on-demand rates — the coverage drop shows up a month later as unexplained cost growth.
Does spot usage count in the denominator?
No — spot can't be covered by commitments, so it's ineligible. Keep it visible as its own pricing-model slice; growing spot share is itself a savings strategy.