How can I tell how many units of a product are being sold?

While Amazon does not reveal this information directly, there are a few methods to figure out the daily/monthly sales volume for any particular product.

1. Look up your product's top-level Best Sellers Rank (BSR)
Amazon has created the Best Seller Rank (BSR) to show how 'hot' each product is, relative to other products in that category. The lower the BSR, the better that product is selling.

To find the BSR of any given product, just scroll down to the 'Product Details' section on that product's Amazon listing.

For instance, let's look at the current BSR for this product - 

You'll see that the top-level BSR is #2,150. The additional BSR (#15) listed underneath the top-level is for sub-categories, and can be ignored.

2. Analyze your top-level BSR with FBA Toolkit
Using FBA Toolkit, you can estimate the daily sales of this product based on the BSR.

Just head to their website, and input your BSR into the proper top-level category.

By doing this, we can assume our sample product is selling roughly 21 to 27 units per day.

While these are not exact calculations, they are solid estimates when doing product research.

3. Bonus: Calculate daily sales revenue
Now that we know our example product is selling 21 to 27 units per day, it's easy to calculate the estimated daily revenue.

If our example product is selling for $24.95, we simply need to multiply that by daily sales -

$24.95 x 21 = $523.95

$24.95 x 27 = $673.65

So the estimated daily revenue for our example product is $523.95 to $673.65.

You can also use tools like Viral Launch to automate these types of calculations in bulk (and more). Check out your Discounts for more information.