Every number on this site is an Ecominsights estimate. Amazon doesn't publish sales figures for products or brands, and the brands on this site don't report their numbers to us. This page explains how the estimates are made, how pages and rankings are built from them, and where they can be wrong.
Where the data comes from
Ecominsights, an Amazon market intelligence platform, records a monthly estimate of units sold and revenue for more than 5 million Amazon US products. For each product we also keep its brand, category, rating, review count and the seller holding the Buy Box. Ecominsights.org shows a small, public slice of that data. The full history for every product, brand and seller is in theEcominsights app.
What the numbers mean
- Estimated units
- How many units of a product we estimate sold on Amazon in a calendar month.
- Estimated revenue
- Estimated units multiplied by the product's selling price that month. Brand revenue is the sum over the brand's products.
- Brand
- The brand name on the Amazon listing. We don't know who legally owns a brand; we report who sells it.
- Who sells it
- Each seller's share of a brand's estimated units, counting the seller that held the Buy Box for each product.
Rounding
Estimates are rounded so they don't look more precise than they are: revenue to one decimal in millions ($1.2M) or to the nearest thousand ($340K), and units to two or three significant figures (34,000, 3,400, 350).
Which months we use
A new month is used only once its data looks complete. It has to hold at least 75% as many products as the month before, and every category with at least 2% of the previous month's revenue has to keep at least 60% of that revenue. A month that fails stays out. Charts show it as no data rather than drawing a fake drop. The latest month on the site is September 2026.
Brand profiles
A brand gets a profile only when all of these are true:
- We have at least 6 months of data for it (while fewer than 6 complete months exist, 4).
- Its estimated revenue in the latest month is at least $5.0K.
- It sold at least 2 different products.
The "At a glance" labels are fixed rules, not opinions:
- Size: Small under $20K a month, Large over $250K, Mid-size in between.
- Trend: the average of the last 3 months against the 3 before (2 against 2 while history is short). Growing above +10%, Declining below −10%, otherwise Stable.
- Ratings: sales-weighted average star rating. Strong at 4.4 or higher, Mixed from 3.9, Weak below that.
- Who sells it: "Mostly one seller" when one seller has 80% or more of units.
Buying guide rankings
Each guide ranks the top 25 products in one Amazon category by estimated units sold in the latest month. Ratings, reviews and badges are shown for context and never change the order. No brand can pay to be included or to move up.
- Variations of the same product, such as colours and sizes, count once (the best-selling version).
- Gift cards and digital codes with a dollar amount in their name are left out.
- Rank change compares with the product's rank in the same category the month before. When a category's coverage changed a lot between the two months, we don't show rank changes.
- Consistent seller: in the top 25 for at least 75% of the months we have, and at least 4 months.
- Fastest rising: the biggest rank gain since last month.
- Best rated in top 10: the highest star rating among the top 10, with at least 50 reviews.
A guide is published only when at least 10 products have 3+ months of data, the category sells at least$50K a month, and people search for it on Google at least 1,000 times a month.
Monthly movers
Movers compare the same products in both months, so a brand adding or losing listings doesn't count as growth or decline. Lists are ranked by the size of the change. A move must be at least 15%. We leave out swings above +500% or below -90%, which are usually stock-outs, restocks or listing changes.
The written summaries
The short "Our read" and "What the sales data says" paragraphs are written by an AI model from the computed figures on the same page. Before publishing, each paragraph is checked automatically: every number in it has to match the page's data, or the paragraph is dropped. They contain no claims about product quality.
Refresh schedule
The site is rebuilt monthly. A month's data is complete a few weeks after the month ends, so pages usually show the month before last. Each page says which month's data it uses.
Limitations
- Estimates can be off for any single product, especially new listings, products that were out of stock for part of the month, and very low sellers.
- Coverage varies by category and month. Category totals cover the products we track, not every product on Amazon.
- Amazon US only. Sales on other marketplaces, brand websites or in stores aren't included.
- Category names come from Amazon's catalog. A few vague ones are renamed for clarity (for example "Automatic" under Health & Household becomes "Blood Pressure Monitors"), and categories that mix unrelated products get no buying guide.
- Nothing here is financial or investment advice.
How this site makes money
As an Amazon Associate we earn from qualifying purchases made through "Check price on Amazon" links. That never affects rankings, which follow estimated sales only. We also link to the Ecominsights app, which this site belongs to. Prices aren't shown on this site; Amazon shows the current price.
Questions or a correction? Contact us.