How to know if a product will sell on Amazon before you buy inventory
The most expensive mistake in Amazon FBA isn’t picking the wrong ads or the wrong price. It’s buying 500 units of something nobody is looking for. The good news is that Amazon shows almost everything you need to estimate demand before you invest. You just have to know how to read it.
1. Sales rank, but over time
Every product has a Best Sellers Rank (BSR) in its category. The lower it is, the more it sells. The problem is that today’s BSR is a snapshot: a product can sit at #800 because it sold ten units yesterday thanks to a one-off deal.
What matters is the film, not the photo. Tools like Keepa show you a product’s BSR over the last few months. Look for products whose rank stays steady in a good range, not isolated spikes.
2. Several sellers doing well, not just one
If only one product sells a lot at the top of a search and the rest barely move, demand is concentrated in one brand. Competing against that is hard.
If five or six different products hold good ranks, demand is spread out. That means buyers aren’t loyal to one brand, and there’s room for one more.
3. Reviews: how many, and how fast
The total number of reviews tells you how hard it will be to compete. A niche where the top results have thousands of reviews takes a lot of investment to gain visibility.
Look at the pace too: if a product that’s only been on the market for a few months is steadily collecting reviews, it’s selling, and there’s still room to get in.
4. What buyers complain about
Read your competitors’ reviews of three stars or fewer. That’s where your opportunity is: the handle that breaks, the size that doesn’t match, the instructions nobody understands. A product with proven demand and repeated complaints is a product you can improve.
5. Seasonality
A product that sells very well in December may sell nothing in March. Check at least a year of history before you decide. Seasonality isn’t a problem, but it changes when you should order inventory and how much.
From gut feeling to a forecast
These five signals let you quickly rule out bad candidates. The next step is to turn them into a number: how many units you expect to sell per month, and with what margin of error.
In my research on forecasting Amazon sales, I found that the history of similar products explains a large part of a new product’s sales. It isn’t magic: it’s using the same data you’ve just seen, in an orderly way.
Before buying inventory, write down how many units you expect to sell in the first month, and why. If you can’t justify the number, you don’t have enough information yet.
The kit Forecast Your Amazon FBA Sales explains the full method, with examples you can apply to your own niche. If you’d rather start with something shorter, the free starter kit below includes the Excel template to start analyzing your own sales.