How is data transfer calculated in Amazon S3

Question

I was going through S2 documentation and was checking out AWS s3 calculator for Standard Storage. 

I didn't understand the meaning of Data Transfer calculation. How it is calculated?

Data Transfer:
Inter-Region Data Transfer Out: 10GB/Month
Data Transfer Out:10GB/Month
Data Transfer In:10GB/Month
Data Transfer Out to CloudFront:.....

Can anyone elaborate on this?

Answer 1

You pay for all traffic going out of AWS which we refer to as Data Transfer Out. You also pay for inter-region traffic.

Suppose,  you have an S3 bucket in Virginia and an EC2 in Oregon. This EC2 downloads a 100MB file from that bucket. You'll pay 100MB of inter-region. If you download the file from your PC, you pay 100MB of transfer out. You always pay for what goes out or to another region. If you partially download a file, you'll be charged that exact amount. That's basically is called data transfer in S3.