This is our second post in a series on how to decipher the byzantine Amazon S3 pricing Schedule.  In our last post we covered S3 pricing for storage, and how it was calculated.  This post will delve into the bandwidth calculations for Amazon S3 storage in hopes that you can avoid that surprise bill that we read about from time to time.

The bandwidth charges for S3 are fairly straightforward but we need to get our terms straight before getting into details about the pricing.  First there is bandwidth in (into Amazon S3) and bandwidth out (data transferred out of Amazon S3).

Bandwidth in represents the bandwidth you use when transferring files into an S3 account.  I would call this uploading files into your account.  This is extremely straightforward.

Bandwidth out represents the bandwidth used whenever anyone transfers a file from, or out of, your S3 account.

So – In simple terms if you are just using S3 to hold your own files your bandwidth in and bandwidth out will be fairly easy to monitor.  But, and this is what gets people, if you’re using Amazon to share files with others, each time a file is downloaded you’re going to be charged for the bandwidth.

Here is the actual pricing and then we’ll work through an example:

Data Transfer In

• All Data transfer in is now free priced at .10 (ten cents) per GB

Data  Transfer Out

• First 1 GB / Monthly is free
• Up to to 10 TB /Monthly  $.12 15 (fifteen twelve cents) per GB
• Next 40 TB / Monthly $.09.11 (eleven nine cents) per GB
• Next 100 TB/ Monthly $.07 09 (nine seven cents) per GB
• Over 350 150 TB/ Monthly $..0508 (eight five cents) per GB

Now let’s move onto an example.  Let’s say you’re a creator of animated videos and you decide to upload a 700 MB movie into your account to share.  You’ve done a great job and you want as many people to see it as possible.

The cost to upload that particular file would be only around free seven cents.  So far, no problem.  Let’s say you email 10 of your friends about the video and they all download and watch it.  The cost to you is again no problem, only around a dollar.  But let’s say that one of your friends tweets the link and it goes viral.  Hey, that’s great right?  You want as many people as possible to see your work.  But, keep in mind that each person that sees it is costing you around  11 8.4 cents.  So, if 1,000 people watch your video your bill will be $84.   Now let’s say that 10,000 people see your video suddenly your cost is over $1,000 $800 for the month.

The moral of the story is that if you’re going to share large files on Amazon S3 you need to keep track of your bandwidth used and be prepared to remove the file sharing on the file if you exceed a certain threshold.

You can check your bandwidth used by logging into your S3 account, and clicking “usage reports.”  I download my data into a CSV file, then sort by usage type and summarize the bandwidth out data to get this information.

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The pricing model for Amazon’s S3 storage is like a math problem with too many variables.  There is storage used, bandwidth used, puts and gets and surely more that get poured into the simmering pot that is your S3 billing charge.  This post will be the first in a series of short posts explaining how the different components are charged for by Amazon.

Storage Used

In simple terms Amazon averages out the storage you have in use, on a daily basis and charges you for the storage used at the end of the month.  The cleverly call this average “TimedStorage-ByteHrs”.

Here’s an example from their website:

Storage Example:
Assume you store 100GB (107,374,182,400 bytes) of standard Amazon S3 storage data in your bucket for 15 days in March, and 100TB (109,951,162,777,600 bytes) of standard Amazon S3 storage data for the final 16 days in March.

At the end of March, you would have the following usage in Byte-Hours:
Total Byte-Hour usage
= [107,374,182,400 bytes x 15 days x (24 hours / day)] + [109,951,162,777,600 bytes x 16 days x (24 hours / day)] = 42,259,901,212,262,400 Byte-Hours.

Let’s convert this to GB-Months:
42,259,901,212,262,400 Byte-Hours x (1 GB / 1,073,741,824 bytes) x (1 month / 744 hours) = 52,900 GB-Months

This usage volume crosses three different volume tiers. The monthly storage price is calculated below assuming the data is stored in the US Standard Region:
1 TB Tier: 1024GB x $0.140 = $143.36
1 TB to 50 TB Tier: 50,176 GB (49×1024) x $0.125 = $6,272.00
50 TB to 450 TB Tier: 1,700 GB (remainder) x $0.110 = $187.00

Total Storage Fee = $143.36 + $6,272.00 + $187.00 = $6,602.36

GOOD GRIEF – Who writes this stuff for them?

Here’s another way of looking at it:

They take measurements of your storage used throughout the month, and charge you based on Actual storage used.  The charges begin at 14 cents per GB and drop from there based on volume.

Here’s a simple example – you have 6 GB of data and that data remains constant throughout the month.  You’ll be charged 6 x .14 or .84 (84 cents) for the storage portion of your bill.

If you keep your storage under 5 GB there is no charge for the storage during your accounts first year.

The next post will deal with data transfer.

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