EC2 instance-hours are calculated according to the following considerations:
- You are billed for an EC2 instance-hour for each hour or partial hour that your instance is in the running state. Instances that are in any other state (for example, stopped, pending, etc.) are not billed.
- Every partial instance-hour is rounded up and calculated as a full instance-hour.
- Each time your instance enters the running state, a new instance-hour begins.
- Each instance is billed separately; partial instance-hours for multiple instances of the same type are not combined into one instance-hour.
Note: If you purchase an EC2 Reserved Instance, you are billed at the beginning of the month for every hour in the current month, according to the terms of your Reserved Instance contract. For more information, see How do EC2 Reserved Instances work?
Here are a few examples of how these considerations work in practice:
- When you run an instance for 30 minutes and then terminate the instance, you are billed for one instance-hour.
- When you run an instance for 10 minutes, stop the instance, and then start the instance again, you are billed for two instance-hours.
- When you run two EC2 instances of the same type for 30 minutes each, you are billed for two instance-hours.
For pricing information, see Amazon EC2 Pricing.