13 Amazon Efficiency Metrics Defined: The 2027 Seller Guide

Amazon efficiency metrics are the numbers that tell you whether your account, inventory and advertising are working or quietly leaking money. In 2027 the list sellers actually need to watch is short: account health metrics that protect your selling privileges, inventory metrics that control FBA storage and restock limits, and advertising and profit metrics that show whether growth is paying for itself. This guide defines each one in plain language, gives the commonly cited targets, and tells you where to find the live number.

Account health metrics

Amazon monitors your performance against targets and can restrict or suspend accounts that miss them. Thresholds and measurement windows can change, so confirm the current figures on the Account Health page in Seller Central. The targets below are the widely cited ones, as summarized by seller education sites such as Emplicit.

Order Defect Rate (ODR)

ODR is the share of orders that received negative feedback, an A to z Guarantee claim or a credit card chargeback. The commonly cited target is below 1% over a 60 day period. It is the single most important health number because it reflects the customer experience directly.

Late Shipment Rate (LSR)

LSR measures the share of seller fulfilled orders confirmed as shipped after the expected ship date. The cited target is below 4% over 10 and 30 day periods. FBA sellers are not measured on this, since Amazon ships the order.

Pre-Fulfillment Cancel Rate

This is the share of orders you cancel before shipping. The cited target is below 2.5% over seven days. Stockouts and bad inventory syncing across channels are the usual causes.

Valid Tracking Rate (VTR)

VTR is the share of seller fulfilled shipments with a valid tracking number. The cited target is above 95%.

On-Time Delivery Rate

This measures the share of packages with tracking that arrive by the estimated delivery date. The cited target is at least 90%, with 95% or higher often recommended.

Account Health Rating

Amazon also shows an overall Account Health Rating. The commonly cited healthy level is 200 or higher. Treat a falling rating as an early warning and fix the underlying metric before it becomes a suspension risk. For how sellers get into trouble and out of it, see our guide on keeping away from an Amazon account suspension.

Inventory efficiency metrics

If you use FBA, inventory efficiency decides how much space you get and how much storage costs you.

Inventory Performance Index (IPI)

IPI is Amazon's score for how efficiently you manage FBA inventory, on a scale of 0 to 1,000, updated weekly. Sources commonly list the components as excess inventory, sell through rate, stranded inventory and in stock rate. Amazon does not publish the exact formula. The minimum threshold has been cited as 400, but Amazon adjusts it from time to time, so check the Capacity Monitor and Inventory Performance dashboards in Seller Central for the current requirement.

Sell through rate

Sell through is units sold over a period divided by the units you had available. A low rate points to overstock, which raises storage fees and drags down IPI. A very high rate with frequent stockouts points to under ordering. You can look up fees in our Amazon storage fees guide.

In stock rate and days of supply

In stock rate shows how often your best sellers are available. Days of supply is current inventory divided by average daily unit sales. Combine it with supplier lead time to set reorder points, so a stockout does not cost you your Buy Box and ranking.

Stranded and excess inventory

Stranded inventory is stock sitting at a fulfillment center without an active listing. Excess inventory is stock beyond what Amazon expects you to sell within its time horizon. Fix stranded units quickly, and run removals or promotions for slow stock before storage fees compound.

Conversion and traffic metrics

Unit Session Percentage

Also called the job success or conversion rate in Business Reports, it is orders divided by sessions. It tells you how well the listing turns visits into sales. Compare it against similar products in your category, not against another category.

Sessions and page views

Sessions count visits to your listings in a period. A rise in sessions with a flat conversion rate suggests your traffic is working but the listing is average. A rise in conversion with flat sessions suggests you should invest in more visibility.

Buy Box percentage

For sellers with competing offers on a listing, Buy Box percentage is the share of page views in which your offer was the featured one. A low figure usually points to price, fulfillment method or account health issues.

Return rate

Returns reduce profit and signal listing or product problems. Review return reasons by SKU, and fix the cause, such as unclear sizing or inaccurate images, instead of only reacting.

Advertising efficiency metrics

ACoS and TACoS

ACoS is ad spend divided by ad attributed sales. TACoS is ad spend divided by total sales, including organic. ACoS tells you whether campaigns are efficient. TACoS tells you whether advertising is building organic demand. If ACoS looks high but TACoS is falling as sales grow, the ad spend may be doing its job.

ROAS

ROAS is ad attributed sales divided by ad spend, the inverse of ACoS. Use whichever your team already reports, and keep it consistent.

Click through rate and conversion rate

Click through rate measures how well your ad and main image attract clicks. Ad conversion rate measures how well the listing converts those clicks. Both together show where a campaign is failing: the creative, the listing or the targeting. For more on ad costs, read our guide on how much Amazon advertising costs.

Profit metrics

Contribution margin per unit

Subtract product cost, shipping to FBA, referral and FBA fees, storage, returns and ad spend from the sale price. If you do not know this number per SKU, the other metrics above can mislead you into scaling a loss.

Return on inventory

Divide gross profit by average inventory cost over a period. This shows whether cash tied up in stock is earning a worthwhile return, and it is useful when deciding which SKUs deserve a reorder.

How to build a weekly review routine

Pick a short dashboard rather than tracking everything. Review account health and IPI weekly, ad metrics twice a week during launches and weekly afterward, and SKU level profit monthly. Software helps: see our overview of ecommerce data analytics and the best Amazon seller tools.

The GTM angle

Every metric above is a symptom that someone sells a fix for. An ODR creeping up is a cue for customer service and listing audit offers. A low IPI or excess inventory is a cue for inventory forecasting software, prep and 3PL services and liquidation partners. A high ACoS with falling TACoS is a cue for PPC management. A sinking Buy Box percentage is a cue for repricing tools.

If you sell to Amazon sellers, segment your outbound by the problem, not by company size alone. Create separate sequences for account health, inventory, advertising and profitability, and write the first line around a visible, public signal, such as a thin review profile, frequent stockouts or an ad heavy listing with weak content. Offer a diagnostic: a free metrics audit, an IPI health check or a PPC efficiency review, with a clear deliverable and timeframe.

Track which metric trigger produces the best reply rate, then double down on it. You can estimate the pipeline each segment could create using the cold email ROI calculator, and find sellers and vendors in the Cruxfinder directory.

Frequently Asked Questions

What are the most important Amazon efficiency metrics?

Start with Order Defect Rate and the other account health metrics, then IPI and sell through for FBA inventory, then TACoS and contribution margin for advertising and profit. These protect the account, control costs and show true profitability.

What is a good Order Defect Rate?

The commonly cited target is below 1% over 60 days. Confirm the current requirement on the Account Health page in Seller Central.

What is a good IPI score?

The score runs from 0 to 1,000 and the minimum threshold has been cited as 400. Amazon can change it, so check the live requirement in Seller Central.

What is the difference between ACoS and TACoS?

ACoS divides ad spend by ad sales, while TACoS divides ad spend by total sales including organic. TACoS shows whether ads are driving overall growth.

Where do I find these metrics?

Account Health, Inventory Performance, Business Reports and the Advertising console in Seller Central cover most of them. Third party tools can combine them into one view.

Takeaways

• Protect the account first: ODR, cancel rate, late shipment, tracking and the health rating.
• Manage FBA with IPI, sell through, in stock rate and days of supply.
• Judge ads with ACoS and TACoS together, and judge SKUs by contribution margin.
• Always verify thresholds in Seller Central because Amazon changes them.
• Selling to Amazon sellers? Build outbound sequences around these metric problems. See Cruxfinder's cold outbound service and the free GTM calculators.