Burstable instances consume CPU credits to maintain running performance. The CPU credit balance accrued during off-peak hours can be used to improve running performance during peak hours and reduce costs. If your burstable instances consume advance or overdrawn CPU credits, you are charged additional fees. The fees for a burstable instance include the instance purchase fee and additional fees.

Instance purchase fee

Burstable instances support the pay-as-you-go, subscription, and preemptible instance billing methods. For more information, see Overview. For information about the pricing of burstable instances, see the Pricing tab of the Elastic Compute Service (ECS) product page.

If the billing method of your burstable instances is pay-as-you-go, you can purchase reserved instances to offset the bills of these pay-as-you-go instances. For more information, see Overview. However, if the instance types of your reserved instances belong to the t5 instance family, the following limits apply:
  • Only zonal reserved instances can be purchased.
  • Reserved instances cannot be split or merged.

Additional fees

The billing of a burstable instance is related to its performance mode. The following section describes the differences between the billing of burstable instances in different performance modes.
Note When you purchase or use a burstable instance, you can choose whether to enable the unlimited mode for the burstable instance. For information about the consumption rules of CPU credits in unlimited mode, see the "Unlimited mode" section in Overview.
  • Standard mode: You are charged only the burstable instance purchase fee. You are charged no additional fees when you use a burstable instance in standard mode.
  • Unlimited mode: You are charged both the burstable instance purchase fee and additional fees that may be incurred in the following cases:
    • The burstable instance has used up advance CPU credits and started to consume overdrawn CPU credits. You are billed and charged for the consumed overdrawn CPU credits by the hour.
    • If a burstable instance has consumed advance CPU credits and is stopped in economical mode, is released, has its configurations changed, or switches to standard mode before the advance CPU credits are replenished, you are charged a lump sum amount for the consumed advance CPU credits.

The following table describes how the additional fees are charged when burstable instances that run in unlimited mode consume CPU credits in different regions.

Region Windows instance (USD/credit) Linux instance (USD/credit)
Region inside the Chinese mainland 0.0008 0.0008
Region outside the Chinese mainland 0.0016 0.0008
Example scenarios for charging additional fees:
  • Scenario 1: If a Linux instance in a region inside the Chinese mainland consumes 100 overdrawn CPU credits after it depletes its advance CPU credits, the additional fee for the instance is calculated based on the following formula: 100 (Number of consumed overdrawn CPU credits) × 0.0008 (Unit price per CPU credit for a Linux instance in a region inside the Chinese mainland) = USD 0.08.
  • Scenario 2: If a Windows instance in a region outside the Chinese mainland first consumes 100 advance CPU credits in unlimited mode and then consumes another 100 advance CPU credits in standard mode, the additional fee is calculated based on the following formula: 100 (Number of consumed advance CPU credits in unlimited mode) × 0.0016 (Unit price per CPU credit for a Windows instance in a region outside the Chinese mainland) = USD 0.16.