AWS EC2 Pricing (Feb 2018) – per second vs hourly?

EC2 pricing at first look seems simple: for on-demand pricing the current prices are listed here, as fractions of a dollar per hour, Here’s a quick look (below) at how these prices are listed for the first few t2 instance types. The list of different instance types is pretty extensive (check out the link for the complete list):

The page says the price is:

by the hour or second (minimum of 60 seconds) with no long-term commitments

and further down:

Pricing is per instance-hour consumed for each instance, from the time an instance is launched until it is terminated or stopped. Each partial instance-hour consumed will be billed as a full hour or per-second depending on which Amazon EC2 instances you run

I added the emphasis as this part is not entirely clear. So to summarize:

  • charged by the second, minimum 60 seconds (this was a recent change, introduced in October 2017, see here)


  • charged as a full hour depending on which Amazon EC2 instances you run

The last part of this last statement is (I think) the key. It refers to which AMI image you’re running, since some images have an hourly charge (if I’m wrong, please leave me a comment and let me know!) :

If you click the Marketplace link, you’ll notice AMI images with commercial products, along with an hourly charge for usage. Ahah, there you go!