If the current bandwidth billing method for the static public IP address of your ECS instance no longer meets your needs, you can change the billing method from pay-by-bandwidth to pay-by-traffic, or from pay-by-traffic to pay-by-bandwidth.
If you use an elastic IP address (EIP) and need to change its billing method, see Change billing methods.
Bandwidth billing for a static public IP
Pay-by-bandwidth: This method bills you based on a specified bandwidth value. Your outbound bandwidth will not exceed this limit. This billing method is suitable for business scenarios that require stable network bandwidth.
Pay-by-traffic: This postpaid method bills you based on your actual data transfer. You set a peak bandwidth to limit your maximum outbound bandwidth and prevent unexpected costs from traffic spikes. This billing method is suitable for business scenarios with fluctuating network bandwidth demands.
ImportantFor the Pay-by-traffic billing method, the peak inbound and outbound bandwidth values are upper limits and not guaranteed service levels. During periods of high resource contention, the peak bandwidth may be limited. If your business requires guaranteed bandwidth, use the Pay-by-bandwidth billing method.
BGP Premium (multi-line) in the China (Hong Kong) region does not support pay-by-traffic billing.
Change from pay-by-bandwidth to pay-by-traffic
This section explains how to change the billing method for an instance's public bandwidth from pay-by-bandwidth to pay-by-traffic in the ECS console. You can also make this change by calling the ModifyInstanceNetworkSpec API.
Go to ECS console - Instances.
In the upper-left corner of the page, select a region and resource group.
The steps to change the public bandwidth billing method depend on the instance's billing method. Follow the appropriate steps for your instance.
Pay-as-you-go instances
Find the target instance. In the All Operations column, choose .
Select Pay-by-traffic and set the peak bandwidth.

Read and select the ECS Terms of Service, and then click Confirm. The change takes effect immediately.
Subscription instances
Find the target instance. In the All Operations column, choose .
In the dialog box that appears, select Downgrade Bandwidth and click Continue.
On the page that appears, select Pay-by-traffic and set the peak bandwidth.

Read and select the ECS Terms of Service, and then click Downgrade. The change takes effect immediately.
You can change the billing method for multiple instances at once by performing batch operations on the Instances page.
Change from pay-by-traffic to pay-by-bandwidth
This section explains how to change the billing method for an instance's public bandwidth from pay-by-traffic to pay-by-bandwidth in the ECS console. You can also make this change by calling the ModifyInstanceNetworkSpec API.
Go to ECS console - Instances.
In the upper-left corner of the page, select a region and resource group.
The steps to change the public bandwidth billing method depend on the instance's billing method. Follow the appropriate steps for your instance.
Pay-as-you-go instances
Find the target instance. In the All Operations column, choose .
Select Pay-by-bandwidth and set the fixed bandwidth value.

Read and select the ECS Terms of Service, and then click Confirm. The change takes effect immediately.
Subscription instances
Find the target instance. In the All Operations column, choose .
In the dialog box that appears, select Modify Peak Bandwidth Value and click Continue.
Select Pay-by-bandwidth and set the fixed bandwidth value.

Read and select the ECS Terms of Service, and then click Confirm. The change takes effect immediately.
You can change the billing method for multiple instances at once by performing batch operations on the Instances page.
Related documents
After you change the billing method, your public bandwidth usage is billed based on the new method. For more information, see Public bandwidth billing.
Depending on the new billing method, you may need to adjust bandwidth limits or quotas.
If you want more flexibility in managing public IP addresses, such as associating them with or disassociating them from ECS instances, you can convert a static public IP address to an elastic IP address.
ImportantIf you convert a static public IP address to an EIP and then change the billing method of the EIP from pay-as-you-go to subscription, you may incur a price difference. Proceed with caution. For more information, see Billing FAQ.