Burstable instances use a CPU credit system to deliver variable performance. Credits accumulate during low-utilization periods and are spent when CPU demand spikes — letting you handle peak traffic without paying for dedicated high-CPU capacity at all times.
The total cost of a burstable instance has two components:
Instance purchase fee: the baseline cost for the instance, regardless of performance mode
Additional fees: applies only in unlimited mode, and only under specific conditions
Instance purchase fee
Burstable instances support three billing methods: pay-as-you-go, subscription, and spot instance. For pricing details, see Detailed pricing overview.
For pay-as-you-go instances, purchase reserved instances to offset hourly bills. If your reserved instances belong to the t5 instance family, the following restrictions apply:
Only zonal reserved instances can be purchased.
Reserved instances cannot be split or merged.
For a general overview of billing methods, see Billing methods overview. For reserved instance details, see Reserved instances overview.
Additional fees
Whether additional fees apply depends on the performance mode.
Standard mode: no additional fees. The instance purchase fee is the only charge.
Unlimited mode: additional fees may apply. See the conditions below.
When you purchase or use a burstable instance, you can choose whether to enable unlimited mode. To switch an instance between standard mode and unlimited mode, or to understand how CPU credits are consumed in unlimited mode, see the "Unlimited mode" section in Overview.
When additional fees apply in unlimited mode
Additional fees are charged when any of the following occurs:
Overdrawn CPU credits consumed: after advance CPU credits are depleted, the instance starts consuming overdrawn CPU credits. These are billed by the hour.
Unpaid advance CPU credits settled: if the instance consumed advance CPU credits and is then stopped in economical mode, released, reconfigured, or switched to standard mode before those advance credits are replenished, the outstanding advance credit balance is charged as a lump sum.
Pricing
The per-credit price varies by region and operating system.
Region | Windows instance (USD/credit) | Linux instance (USD/credit) |
Inside the Chinese mainland | 0.0008 | 0.0008 |
Outside the Chinese mainland | 0.0016 | 0.0008 |
Calculation examples
Scenario 1: Overdrawn CPU credits (Linux, inside the Chinese mainland)
A Linux instance in a region inside the Chinese mainland consumes 100 overdrawn CPU credits after depleting its advance CPU credits.
Additional fee = 100 credits × USD 0.0008/credit = USD 0.08
Scenario 2: Advance CPU credits settled on mode switch (Windows, outside the Chinese mainland)
A Windows instance in a region outside the Chinese mainland first consumes 100 advance CPU credits while in unlimited mode, then consumes another 100 advance CPU credits in standard mode before the original credits are replenished.
Additional fee = 100 credits × USD 0.0016/credit = USD 0.16
Advance CPU credits consumed while the instance was in standard mode are not included in this calculation.
Region | Windows instances (yuan/credit) | Linux instances (yuan/credit) |
Regions in mainland China | 0.005 | 0.005 |
Regions outside mainland China | 0.01 | 0.005 |
Examples of additional charges:
Example 1: The region is in mainland China, the instance type is Linux instance, and 100 excess CPU credits were consumed after advance CPU credits were exhausted. The additional charge = 100*0.005 = 0.5 yuan.
Example 2: The region is outside mainland China, the instance type is Windows instance, 200 advance CPU credits were consumed, and the mode was switched to performance constrained mode when advance CPU credits were restored to 100. The additional charge = 100*0.01 = 1 yuan.