Burstable instances consume CPU credits to ensure running performance. The CPU credit balance accrued during off-peak hours can be used to improve running performance during peak hours to reduce costs. If your burstable instances consume advance CPU credits or overdrawn CPU credits, you are charged additional fees. Therefore, the fees for a burstable instance contain 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 Billing method overview. For information about the pricing of burstable instances, see the Pricing tab of the ECS page.

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

Impact of performance modes on billing (additional fees)

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 billing rules of the CPU credits in unlimited mode, see the "Unlimited mode" section in Overview.

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:
  • Standard mode: You are charged only when you purchase burstable instances. You are not charged additional fees when you use the burstable instances.
  • Unlimited mode: You are charged additional fees in addition to the instance purchase fee in the following cases:
    • Advance CPU credits are used up. Overdrawn CPU credits are used. You are billed and charged by hour.
    • Advance CPU credits are used, and the performance mode is changed to the standard mode before the advance CPU credits are replenished. You are charged a lump sum and the CPU credit balance remains unchanged.
    • Advance CPU credits are used, and the instance is stopped (with the economical mode enabled), is released, or has its configurations changed before the advance CPU credits are replenished. You are charged a lump sum.

The following table describes how additional fees are charged for burstable instances that run in unlimited mode.

Region Windows instance (USD/credit) Linux instance (USD/credit)
Mainland China 0.0008 0.0008
Outside mainland China 0.0016 0.0008