How to estimate amazon sales based on # of reviews

dont really know about that but I can telling you that using merchantwords.com has helped me get a good idea of search volume at least

Didn't find merchant words helpful at all. Not worth the monthly fee

Nothing that is practical/useful.

That's what I wish Amazon had - sales data. However, since it doesn't have it, my sales/profit cannot be predictable. That's a shame, too. I like Amazon, but not as a seller.

I like/need more predictability - especially in knowing how to maximize my price/profit.

I honestly have not done any tests, BUT, by looking at the kindle on Amazon and knowing that 43.7 million Kindle devices have been sold, you can get a good idea about how many people review to how many people buy.
Compare the 43.7 million bought to the reviews on the Kindles here http://www.amazon.com/s/ref=nb_sb_no...eywords=kindle

Hopefully you find something worthwhile.

Well, reviews completely depend on customer satisfaction with their services. If they are fully satisfied with their services, then the ratio of reviews might be 5 out of 10.

I use FBAtoolkit.
FBA Toolkit

I suggest using camelcamelcamel. I think it works very well. You can just go to their site or use it as a plug-in for your browser. I use it on Firefox. You just have to put in the ASIN number. It will show a bar graph of sales with the selling price over different time frames such as 3 months, 6 months, etc. It also shows the sellers as Amazon, 3rd part new and 3rd party used.

This is primarily what I look at when selecting products for my inventory. I occasionally look at page rank and almost never concern myself with reviews. I also look at the amount and pricing of the current competition.

As for feedback I think the estimate of 10 to 15% mentioned above is a bit high. Mine is below 5% after two years.

The estimation based on No of reviews only are not correct always. There are several things which needs to be estimated in order get some reliable stats. These includes
1. BSR of the products in the particular category
2. No of reviews over a period of time.
3. Organic rank changes
4. Price changes
5. No of sellers
and many other factors.
These estimations can be done manually, but you should be a developer in order to do so.
Alternative?
You can use Eglim for this purpose.

As accurate as you're going to get is by adding the product to cart and changing the quantity to 999, then watching to see how much the available quantity decreases over the next several days. This only works if the quantity available is less than 999, if they don't replenish inventory while you are monitoring this, and if they aren't doing something like reserving product and then releasing it. Getting the right sales number also hinges on primarily 1 seller being in control of the buy-box. Some tools out there probably automate this.

The volume on Amazon is so high that it's hard to estimate. All I'll say is that if you pick your product well, you'll have more sales than you could've predicted. I had a site that was ranking at the top of google for various keywords for several years. It has since fallen off a bit, but still does well over $250K per year. One of my little rinky dink products that I used as an add-on has sold a total of 2000 units (roughly) over the last 5 years. On Amazon alone last year, it sold over 5300 and was priced more expensive to cover the fees.

My sales last year of my primary product were around 22K units. It took roughly 4.5 years of e-commerce sales to hit that number.

i Dont think any one can except the seller himself or amazon i have seen alot of bad products with low sale volume but with good reviews and some hot products with high sale volume with low reviews.

there is no way for you to track the sales based on the review. However, there are 2 ways for you to estimate the sales.
1. you can basically track the rank/ category rank/ sub category rank. Each ranking means different sales volume
2. sell under the same listing (have one to sell?)
go back to the seller central, and find the report
you will see all the sessions which were stolen from the competitors' listings.
once you know the session, you can calculate the sales based on certain conversion rate, like 10%, 15%. This is very dangerous, since many sellers on amazon have copyright for the products, and your account will be suspended because you are selling under their listings.

Yes, you can have this kind of estimation, you can determine the number using products where you have public data about sales.
Also you can have a better view if you get all reviews amazon, bestbuy, etc. You can get all review using a tool like FeedCheck.co