Log on to the Billing Management console. On the Account Overview page, you can view the Available Credit section. An available credit indicates the available amount that you can use to purchase resources.
Available credit = Account Balance and Refund+Credit Limit-Unpaid and To be billed. The following list describes each item:
Credit limit: the maximum amount of credit that your service manager requested for your account and Alibaba Cloud extended to the account based on internal evaluation. The credit limit is provided based on a combination of your historical costs and the evaluation of your business status.
Account balance and refund: the balance of your Alibaba Cloud account before you purchase a resource and the refund for a resource that you purchased by using the balance of your credit limit.
Unpaid and To be billed: the uncleared amount of charges for an Alibaba Cloud service that you use in a bill and the pay-as-you-go resources that still run in the current month.
The following figure shows an example. In this example, the balance of the credit limit in the account is USD 29531.58. You can use the balance to purchase a subscription resource whose price is less than or equal to USD 29531.58 (after-tax), or use a pay-as-you-go resource until the balance is depleted. 
And it can be seen that the Available Credit is equal to Balance and Refund plus Credit Limit minus Unpaid and To be Billed.