How can I calculate my burst credit billing on my EC2 instance?

Resolution

Note: Burst credit billing applies to EC2 burstable instance types only. For example, T4g, T3a, and T3 instance types, and the previous generation T2 instance types.

You can configure burstable instances to run in one of two modes: standard mode or unlimited mode.

You can check whether your burstable performance instance is configured as unlimited or standard using the EC2 console or the AWS Command Line Interface (AWS CLI). For more information, see View the credit specification of a burstable performance instance and View the default credit specification.

Note: If you receive errors when running AWS CLI commands, make sure that you’re using the most recent version of the AWS CLI.

Billing in standard mode

In standard mode, you're charged using the standard On-Demand hourly rate for your instance.

Billing in unlimited mode

In unlimited mode, the hourly instance price automatically covers all CPU usage spikes for the shorter of the following:

• The time that the instance's average CPU utilization is at or below the baseline over a rolling 24-hour period.
• The instance's lifetime.

If the instance runs at a higher CPU utilization for a prolonged period, it can do so for a flat additional rate per vCPU-Hour. For information on vCPU-Hour charges, see T2/T3/T4g Unlimited Mode Pricing.

Credits that are spent by an instance in unlimited mode after it depletes its accrued credit balance are called surplus credits. For information on when surplus credit charges occur, see Surplus credits can incur charges.

You can use the Amazon CloudWatch metric CPUSurplusCreditsCharged to see surplus credits that are charged for your instance. For more information, see Additional CloudWatch metrics for burstable performance instances.

For examples of how EC2 burstable instances in unlimited mode spend credits and are charged, see Unlimited mode examples.

Related information

Key concepts and definitions for burstable performance instances