I originally wrote this post in September 2012. Recently at their re:Invent event, Amazon announced reduction in their storage prices by 24-28% (http://aws.typepad.com/aws/2012/11/amazon-s3-price-reduction-december-1-2012.html). Yesterday Microsoft announced similar price reduction (http://blogs.msdn.com/b/windowsazure/archive/2012/12/05/announcing-reduced-pricing-for-windows-azure-storage.aspx). I have updated this blog post taking these price reductions into consideration and including them in my calculator below. Please note that both Amazon and Windows Azure have reduced only the storage charges. They have not changed the transaction charges or the bandwidth (Egress) charges. The new prices for Amazon became effective as of 01-December-2012 while that for Windows Azure will become effective on 12-December-2012.
Few months back, I wrote a few blog posts comparing Windows Azure Blob Storage and Amazon S3 services. You can read those blog posts here:
Since pricing for both of these services are changing quite frequently and depended upon a number of factors, it was not possible for me to pinpoint exactly which service is cheaper. I created a simple calculator where you can input appropriate values and compare the cost of both of these services to you.
As mentioned in my other blog posts, the pricing depends on 3 factors in both services:
In this simple calculator, I took only first two factors into consideration. Again when it comes to storage costs, both services offered a tiered pricing scheme, which I have not considered.
A few comments: