Bandwidth: Amazon Sales Estimate Confidence Checker

Tells you how much to trust an Amazon sales estimate before you commit capital. Reads public page signals. No account needed.

Amazon sellers commit real money based on monthly sales estimates. Those estimates are often imprecise, and nothing on the page tells you when. Bandwidth does not give you another estimate. It tells you how much to trust the ones you already have. WHY ESTIMATES GO WRONG Almost every sales estimate comes from the same public signal: the Best Sellers Rank, converted into units sold. That conversion breaks down in situations you can actually recognise: A listing with 80 variations shares a single rank across all of them, while the estimate reads as if it described the one item you are looking at. A rank that swings widely from day to day cannot point to a stable sales level, so any single number is a snapshot of a moving value. Deep in the long tail the curve is flat, and estimates of a few units per month become hard to tell apart. A listing with almost no history has too little behind its rank to support a confident reading. The error is not the same everywhere. On some products the estimate is reasonable, on others it is far off. Most tools present both cases identically. WHAT BANDWIDTH DOES On an Amazon product page, Bandwidth reads the public signals that determine whether an estimate can be trusted, and shows a reliability verdict before you commit money. Every verdict explains itself. Not "reliability: low" but "this listing groups 87 variations" or "the rank swung 340% over 30 days". You see the reasoning, not just a score. WHEN IT DOES NOT KNOW, IT SAYS SO If a page does not expose enough signals, Bandwidth reports that there is not enough data to judge, instead of inventing a confident answer. A tool meant to measure trust cannot afford to say "trustworthy" when it knows almost nothing. BUILT ON MEASUREMENTS The thresholds are not guesses. They were calibrated against a random sample of 335 real products across five European and North American Amazon marketplaces. Review thresholds differ by marketplace, because typical review volume varies widely between one country and another, and a single threshold would flag half the listings in one market and almost none in another. PRIVACY No servers. No account. No network requests. No analytics. Everything is computed inside your browser and stays on your device. Beyond access to Amazon product pages, the only permission requested is local storage, used to keep rank history on your machine. RANK HISTORY Amazon shows only the current rank, so Bandwidth records one data point per product per visit and builds the history itself. On a first visit it says the history is still building, rather than implying a stability it cannot verify yet. The longer you use it, the more it can tell you. WHERE IT WORKS Bandwidth works on Amazon product pages in the United States, the United Kingdom, Germany, Italy, Spain and France. The interface follows your browser language and is available in English, Italian, German, Spanish and French. WHO IT IS FOR Built for online arbitrage and wholesale sellers who look at dozens of products a day on thin margins, where one bad estimate turns into inventory that does not sell. Free, with no account and no sign-up.