Updated 4 Jul 2026 • 5 mins read
The AWS Cost Efficiency Metric Explained:
AWS launched a Cost Efficiency metric in Cost Optimization Hub at re:Invent 2025: a single zero-to-one-hundred score of how optimized your addressable spend already is. This guide explains the formula, what it includes, AWS's published benchmarks from 71,000 customers, how to use it in FinOps, and its limits.
Cloud optimization has always had a measurement problem: savings found, savings realized, coverage, utilization, effective rates, every team reporting a different number, none of them comparable, and executives left asking the only question they ever had: are we actually efficient? At re:Invent 2025, AWS shipped its answer: a Cost Efficiency metric, one standardized, automatically generated score of how optimized your spend already is.
This guide explains exactly how the metric works, where to find it, what AWS's own benchmark data says a good score looks like, how to fold it into a FinOps practice, and, just as important, what the metric does not measure and how to avoid gaming it.
Key takeaway The AWS Cost Efficiency metric is a free, automatically generated score in Cost Optimization Hub, computed as one minus potential savings divided by total optimizable spend, times one hundred. It updates daily on recent cost-and-usage history, blends workload optimization (rightsizing, idle, modernization) with rate optimization (Savings Plans, Reserved Instances), and can be viewed by account and region. AWS's analysis of 71,000+ customers puts the median at 83 and the mean at 79, so treat the low eighties as par, and remember it measures how well you act on AWS's recommendations, which is necessary but not sufficient for true efficiency.
What the Cost Efficiency Metric Is
The metric is a single score from zero to one hundred, generated automatically in AWS Cost Optimization Hub, the free service that aggregates optimization recommendations across your organization. A score of one hundred means the Hub currently sees no unrealized savings in your optimizable spend; lower scores mean identified opportunities are sitting untaken. It refreshes daily, is computed from your recent cost and usage history, and can be sliced by account and region, which quietly makes it the first native way to compare business units on optimization discipline using one consistent yardstick. Announced around re:Invent 2025, it answers a request the FinOps community had made for years: a common efficiency number that does not require a PhD to interpret or a committee to reconcile.
The Formula, Unpacked
Cost Efficiency equals one minus potential savings divided by total optimizable spend, multiplied by one hundred. Both inputs deserve a careful read. Potential savings is the sum of what Cost Optimization Hub's current recommendations would save: rightsizing, idle-resource cleanup, modernization to newer generations, and commitment purchases. Total optimizable spend is the denominator of spend those recommendation types can address, not your entire bill. Two consequences follow. First, the score rises when you act: purchase a Savings Plan, delete idle resources, rightsize an oversized instance, and the untaken-savings numerator shrinks. Second, the score can move when you do nothing: as AWS releases new recommendation types, previously invisible opportunities appear and scores can dip, which AWS itself notes, so treat step changes as new information, not regressions.
What the Score Includes
| Component | What it covers | Where the data comes from |
|---|---|---|
| Rightsizing | Oversized instances and resources versus observed utilization | Compute Optimizer analysis (memory metrics improve it sharply) |
| Idle resources | Resources billing without meaningful use | Cost Optimization Hub idle detection, including newer checks like unused NAT gateways |
| Modernization | Older generations where newer ones offer better price-performance | Cost Optimization Hub modernization recommendations |
| Rate optimization | Uncovered steady usage where Savings Plans or Reserved Instances would apply | Commitment coverage and utilization analysis |
What Good Looks Like: AWS's Own Benchmarks
Uniquely, this metric shipped with peer data. AWS's State of Cost Efficiency report, published in 2026, analyzed optimization patterns across more than 71,000 anonymized, opted-in customers and put the median score at 83 with a mean of 79, the gap driven by a long tail of less-optimized accounts. Dispersion tells its own story: smaller customers span a 52-point range between their least and most efficient members, while larger customers cluster within 35 points, consistent with dedicated FinOps teams producing steadier discipline. And the report's most actionable finding is about data, not spending: customers with EC2 memory metrics enabled see 8 to 30 percentage points higher savings per rightsizing recommendation, yet only 17.7 percent of eligible customers have them on. AWS's top quartile shares three habits: memory metrics enabled, rightsizing before committing, and optimization treated as an ongoing process rather than an event.
How to Use It in Your FinOps Practice
- As an executive headline. One trend line, benchmarked against a published median, finally gives leadership the are-we-efficient answer; report it quarterly beside spend.
- As a team-level comparison. Account- and region-level views let you compare business units on one yardstick, and pair naturally with allocation-based accountability.
- As a complement, not a replacement. Run it alongside effective savings rate, coverage and utilization, waste share, and unit costs in your FinOps KPI scorecard; each metric covers blind spots the others have.
- As a to-do list generator. The score is literally derived from open recommendations, so the fastest path upward is working the Hub queue, highest-savings items first.
What the Metric Does Not Measure
Honest use requires knowing the boundaries. The score reflects only what AWS's recommendation engines can see: it does not know that an entire workload is architecturally wasteful, that a service could move to spot or serverless, that your Kubernetes requests are double actual usage inside the nodes, or that an AI feature is burning uncached tokens, categories where real money hides beyond the formula's denominator. It is also single-provider by definition, so multi-cloud estates still need a cross-provider efficiency view, and it measures cost efficiency rather than cost-versus-value, the unit-economics question that cloud optimization ultimately serves. Treat a high score as necessary hygiene, not sufficient efficiency, and keep the broader optimization practice running around it.
How to Raise Your Score, in Order
- Turn on the data: enable EC2 memory metrics via the CloudWatch agent or supported observability tools, the single highest-leverage step per AWS's own analysis.
- Clear the idle queue: orphaned volumes, idle load balancers, unused NAT gateways and Elastic IPs, zero-risk deletions that move the numerator immediately.
- Rightsize with the new data, and modernize generations in the same pass.
- Then, and only then, cover the measured baseline with commitments, using the portfolio discipline that keeps coverage and utilization paired.
- Make it a cadence: review the Hub queue monthly per account owner, and watch the score as a trend, not a trophy, alongside the rest of your AWS cost management practice.
Where It Fits in the Bigger re:Invent Picture
The metric did not arrive alone: re:Invent 2025 delivered a wave of cloud financial management launches, Database Savings Plans, FOCUS 1.2 in Data Exports, Kubernetes labels in split cost allocation, managed anomaly monitors, AI-powered forecasting, and natural-language cost analysis, that collectively push optimization from a reporting exercise toward an operating discipline, a shift our re:Invent partner guide and AWS cost optimization best practices unpack. The efficiency score is the scoreboard for that discipline: for the first time, the provider itself tells you, daily, how much of the game you are leaving unplayed.
Conclusion
The AWS Cost Efficiency metric gives the industry something it never had: a free, standardized, provider-published efficiency score with real peer benchmarks attached, median 83, mean 79, and a formula simple enough to explain in a sentence. Used well, as an executive trend line, a team comparison, and a to-do list generator anchored by companion KPIs, it sharpens any FinOps practice. Used alone, it measures only what AWS can recommend, on one cloud, with gaming vectors left open. The teams that win with it will be the ones that raise the score by actually becoming efficient, memory metrics on, rightsizing before committing, cadence over cleanup, and measure everything the score cannot see. Providing that fuller picture, efficiency across every account, cluster, cloud, and AI workload you run, is exactly what Opslyft is for.
FAQs
A single zero-to-one-hundred score in AWS Cost Optimization Hub, launched around re:Invent 2025, that measures what share of your optimizable spend is already optimized. It is free, generated automatically, refreshed daily, and viewable by account and region.
One minus potential savings divided by total optimizable spend, multiplied by one hundred. Potential savings sums the Hub's open recommendations, rightsizing, idle cleanup, modernization, and commitments, and the denominator is the spend those recommendation types can address, not your whole bill.
AWS's analysis of more than 71,000 opted-in customers puts the median at 83 and the mean at 79, so the low-to-mid eighties is par and the top quartile sits meaningfully higher. Trend matters more than any single reading, since new recommendation types can shift scores.
In AWS Cost Optimization Hub within the Billing and Cost Management console. The Hub is free; if it is not yet enabled for your organization, enabling it is the first step, and the score appears alongside the recommendation queue it is derived from.