Classic Load Balancer (CLB) supports the payasyougo billing method. You can release a payasyougo CLB instance anytime.
Adjustments are made to the billable items of CLB. Beginning 00:00:00 (UTC+8), December 1, 2024, the following new billable items are used by payasyougo CLB instances:
Instance fee is renamed public IP retention fee.
A billable item instance fee is added.
For more information, see CLB billing adjustments.
CLB provides highperformance instances and sharedresource instances. Sharedresource instances are no longer available for purchase. The CLB instances described in this topic refer to highperformance CLB instances.
Billing rules
Item  Description 
Billing rules  The payasyougo billing method allows you to use resources before you pay for the resources. Bills are generated and fees are deducted after each billing cycle. 
Use scenarios  The payasyougo billing method is ideal for the following scenarios:

Billing cycles  Fees are calculated on an hourly basis (UTC+8). When the fees within a billing cycle are generated, a new billing cycle begins. For example, if you create a payasyougo CLB instance at 09:30:00 (UTC+8) and release the instance at 12:30:00 (UTC+8), the usage duration is 4 hours. Note If the total amount of the balance and vouchers in your Alibaba Cloud account is less than the fee that you need to pay, you are notified by text message or email. 
Configuration changes  The following figure shows the metering methods and configuration changes of payasyougo CLB instances.
For more information, see Modify the configurations of payasyougo CLB instances. 
Effective time of configuration changes  If you change the configuration of a CLB instance but do not change the metering method of Internet data transfer, the change immediately takes effect. If you change the configuration of a CLB instance and also change the metering method of Internet data transfer, the changes take effect at 00:00:00 (UTC+8) on the next day. 
Bandwidth limits 
For more information, see Bandwidth limits. 
Metering methods
Payasyougo CLB instances support the paybyLCU and paybyspecification metering methods. The billable items of a CLB instance vary based on the metering method and network type of the CLB instance, and the metering method of Internet data transfer.
In the following table, a hyphen () indicates that you are not charged the fee and a check mark (✔) indicates that you are charged the fee.
PaybyLCU (new)
Network type  Metering method of Internet data transfer  Performance  Instance fee  Specification fee and LCU fee  Internet data transfer fee  
Specification fee  LCU fee  Data transfer fee  Bandwidth fee  
Internetfacing  Paybydatatransfer  Automatically scales on demand. The upper limit is defined in the s3.large specification.  ✔    ✔  ✔   
Internalfacing    Automatically scales on demand. The upper limit is defined in the s3.large specification.      ✔     
Paybyspecification
Network type  Metering method of Internet data transfer  Performance  Instance fee  Specification fee and LCU fee  Internet data transfer fee  
Specification fee  LCU fee  Data transfer fee  Bandwidth fee  
Internetfacing  Paybydatatransfer  Determined by the specification that you purchase. The highest specification that you can select is s3.large.  ✔  ✔    ✔   
Paybybandwidth  Determined by the specification that you purchase. The highest specification that you can select is s3.large.  ✔  ✔      ✔  
Internalfacing    Determined by the specification that you purchase. The highest specification that you can select is s3.large.    ✔       
Instance fee
Description
You are charged instance fees for CLB instances on an hourly basis. If the usage duration in a billing cycle is less than 1 hour, the usage duration is rounded up to 1 hour. The usage duration refers to the period of time from when a CLB instance is created to when the CLB instance is released.
NoteYou are not charged instance fees for internalfacing CLB instances.
Calculation formula
Instance fee = Instance unit price (USD/hour) × Duration of usage (hours)
Pricing
Example
Alice purchased an Internetfacing CLB instance at 10:00:00 (UTC+8) on January 20, 2022 in the China (Hangzhou) region and released the CLB instance at 12:34:00 (UTC+8) on January 21, 2022. The instance fee is calculated based on the following formula:
Instance unit price in the China (Hangzhou) region = USD 0.003 per hour Usage duration = 27 hours Instance fee = USD 0.003 per hour × 27 hours = USD 0.081
Specification fee and LCU fee
Specification fee
You are charged specification fees only for paybyspecification CLB instances. The following section describes the key metrics of highperformance CLB instances. The performance of a CLB instance varies based on the specification.
 Maximum number of connections
The maximum number of connections that can be established to a CLB instance. When the number of existing concurrent connections reaches the upper limit, new connection requests are dropped.
 Connections per second (CPS)
The maximum number of new connections that can be established to a CLB instance per second. When the actual number reaches the upper limit, new connection requests are denied.
 Queries per second (QPS)
The maximum number of HTTP or HTTPS requests that can be processed per second. This metric is specific to Layer 7 listeners. When the actual number reaches the upper limit, new requests are denied.
Example: Alice purchased an Internetfacing CLB instance of the slb.s2.small specification at 10:00:00 (UTC+8) on January 20, 2022 in the China (Hangzhou) region and released the CLB instance at 12:34:00 (UTC+8) on January 21, 2022. The specification fee is calculated based on the following formula:
Unit price of the slb.s2.small specification in the China (Hangzhou) region = USD 0.05 per hour
Usage duration = 27 hours
Specification fee = USD 0.05 per hour × 27 hours = USD 1.35
LCU fee
A Load Balancer Capacity Unit (LCU) is the smallest unit that is used to measure resources consumed by CLB instances.
Definition
You are charged LCU fees of CLB on an hourly basis. The billing cycle is 1 hour. If the usage duration in a billing cycle is less than 1 hour, the usage duration is rounded up to 1 hour.
LCU fee per hour = LCU unit price (USD per LCU) × Number of LCUs consumed per hour
Number of LCUs per hour = max {Number of LCUs consumed by new connections, Number of LCUs consumed by concurrent connections, Number of LCUs consumed by data transfer, Number of LCUs consumed by rule evaluations}
LCUs are used to measure the performance when CLB processes traffic. The performance metrics of an LCU vary based on the protocol of the CLB listener.
TCP traffic
Metric
Description
Unit
LCU coefficient
Calculation
Number of new connections
The number of new TCP connections processed per second.
Seconds
800
The system collects all CPS values within a billing cycle and then divides the largest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Largest CPS value/LCU coefficient
Number of concurrent connections (CONNS)
The number of concurrent TCP connections per minute.
Minutes
100,000
The system collects all CONNS values within a billing cycle and then divides the largest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Largest CONNS value/LCU coefficient
Amount of data transfer
The amount of data transfer over TCP that is processed by CLB. Unit: GB.
Hours
1 GB
The system divides the total amount of data transfer over TCP within a billing cycle by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Total amount of data transfer/LCU coefficient
UDP traffic
Metric
Description
Unit
LCU coefficient
Calculation
Number of new connections
The number of new UDP connections processed per second.
Seconds
400
The system collects all CPS values within a billing cycle and then divides the largest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Largest CPS value/LCU coefficient
Number of CONNS
The number of concurrent UDP connections per minute.
Minutes
50,000
The system collects all CONNS values within a billing cycle and then divides the largest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Largest CONNS value/LCU coefficient
Amount of data transfer
The amount of data transfer over UDP that is processed by CLB. Unit: GB.
Hours
1 GB
The system divides the total amount of data transfer over UDP within a billing cycle by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Total amount of data transfer/LCU coefficient
HTTP and HTTPS traffic
Metric
Description
Unit
LCU coefficient
Calculation
Number of new connections
The number of new HTTP and HTTPS connections processed per second.
Seconds
25
The system collects all CPS values within a billing cycle and then divides the largest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Largest CPS value/LCU coefficient
Number of CONNS
The number of concurrent HTTP and HTTPS connections per minute.
Minutes
3,000
The system collects all CONNS values within a billing cycle and then divides the largest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Largest CONNS value/LCU coefficient
Amount of data transfer
The data transfer over HTTP and HTTPS that is processed by CLB. Unit: GB.
Hours
1 GB
The system divides the total amount of data transfer over HTTP and HTTPS within a billing cycle by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Total amount of data transfer/LCU coefficient
Number of rule evaluations
The product of the number of forwarding rules processed by CLB and the number of queries per second (QPS). The first 25 forwarding rules are free of charge. If the number of forwarding rules processed by CLB is greater than 25, the following formula applies: Number of rule evaluations = QPS × (Number of forwarding rules processed by CLB  25). If the number of forwarding rules is less than 25, the following formula applies: Number of rule evaluations = QPS.
Seconds
1,000
The system collects the number of forwarding rules and all QPS values within a billing cycle and uses the largest QPS value to calculate the number of rule evaluations. Then, the system divides the number of rule evaluations by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated based on the following formula:
Number of LCUs = Number of rule evaluations/LCU coefficient
The number of LCUs that are consumed by a CLB listener per hour is equal to the largest number of LCUs consumed for different metrics. The LCU fee of a CLB instance is the sum of the LCU fees for all listeners.
LCU unit prices
After the hourly metrics of a CLB instance are converted into LCUs, the hourly LCU consumption is calculated based on the actual usage. The LCU consumption is accurate to 0.000001 LCU. For example, if you consume 0.1 LCU in an hour, the LCU fee for the hour is calculated based on the following formula: 0.1 × 0.007 = USD 0.0007.
The prices in the following table are for reference only. The prices on the buy page shall prevail.
Billable item  Unit price of LCUs (USD per LCUhour 
LCU  0.007 
Billing examples
Alice created a paybyLCU CLB instance in the China (Hangzhou) region at 08:10:00 (UTC+8) on June 8, 2022, and configured a TCP listener and an HTTP listener for the instance. Alice released the instance at 08:50:00 (UTC+8) on June 8, 2022. The following table describes the largest CPS value, the largest CONNS value, the amount of data transfer, and the largest number of rule evaluations of the CLB instance from 08:10:00 (UTC+8) to 08:50:00 (UTC+8).  
Metric  TCP  HTTP 
CPS per second  The largest CPS value within the hour is 1,600. The number of LCUs is calculated based on the following formula:
 The largest CPS value within the hour is 100. The number of LCUs is calculated based on the following formula:

CONNS per minute  The largest CONNS value within the hour is 480,000. The number of LCUs is calculated based on the following formula:
 The largest CONNS value within the hour is 12,000. The number of LCUs is calculated based on the following formula:

Data transfer per hour  The data transfer over TCP processed by CLB within the hour is 4 GB. The number of LCUs is calculated based on the following formula:
 The data transfer over HTTP processed by CLB within the hour is 3.6 GB. The number of LCUs is calculated based on the following formula:

Number of rule evaluations per second  0  For example, 40 forwarding rules are created for the HTTP listener, and the highest QPS value within the hour is 400. In this example, the number of forwarding rules that you configured exceeds the free quota. The largest number of rule evaluations within the hour is calculated based on the following formula:
The number of LCUs is calculated based on the following formula:

In this example, the metric for which the TCP listener consumes the largest number of LCUs is the number of concurrent connections (4.8 LCUs), and the metric for which the HTTP listener consumes the largest number of LCUs is the number of rule evaluations (6 LCUs). 
LCU fee for the TCP listener = USD 0.007 × 4.8 = USD 0.0336
LCU fee for the HTTP listener = USD 0.007 × 6 = USD 0.042
Hourly LCU fee for the CLB instance = LCU fee for the TCP listener + LCU fee for the HTTP listener = USD 0.0336 + USD 0.042 = USD 0.0756
The average monthly LCU fee for the CLB instance is calculated based on the following formula: USD 0.0756 × 24 × 30 = USD 54.432
.
Internet data transfer fee
Data transfer fee (charged for paybydatatransfer Internetfacing instances)
Description
You are charged for outbound data transfer over the Internet. You are not charged for inbound data transfer over the Internet. You are charged and billed for paybydatatransfer Internetfacing CLB instances on an hourly basis. If the usage duration is less than 1 hour in a billing cycle, the usage duration is rounded up to 1 hour.
Calculation formula
Within a billing cycle: Data transfer fee = Unit price of data transfer (USD/GB) × Amount of data transfer (GB)
Pricing
Example
Alice purchased an Internetfacing paybydatatransfer CLB instance at 10:00:00 (UTC+8) on January 20, 2022 in the China (Hangzhou) region and released the CLB instance at 12:34:00 (UTC+8) on January 21, 2022. The outbound data transfer over the Internet is 5 GB.
Unit price of data transfer in the China (Hangzhou) region = USD 0.125 per GB Outbound data transfer: 5 GB Data transfer fee = USD 0.125 per GB × 5 GB = USD 0.625
Bandwidth fee (charged for paybybandwidth Internetfacing instances)
Description
You are charged and billed for paybybandwidth Internetfacing CLB instances on a daily basis. If the usage duration in a billing cycle is less than 1 hour, the usage duration is rounded up to 1 hour. If the usage duration is less than one day, you are charged based on the number of hours that you use a CLB instance. The usage duration is the duration for which a CLB instance uses bandwidth.
The bandwidth fee of a paybybandwidth Internetfacing CLB instance is calculated based on a tiered pricing model with 5 Mbit/s as the standard bandwidth value.
If you modified the maximum bandwidth of a CLB instance within a billing cycle, you are charged based on the highest value on that day.
NoteFor paybybandwidth CLB instances, the maximum inbound bandwidth is the same as the maximum outbound bandwidth.
Calculation formula
For a CLB instance whose maximum bandwidth is from 1 to 5 Mbit/s, the bandwidth fee is calculated by using the following formula: Bandwidth fee = Maximum bandwidth × Bandwidth unit price × Usage duration. For a CLB instance whose maximum bandwidth is higher than 5 Mbit/s, the bandwidth fee is calculated by using the following formula: Bandwidth fee = [5 × Unit price of bandwidth from 1 to 5 Mbit/s + (Maximum bandwidth  5) × Unit price of bandwidth higher than 5 Mbit/s] × Usage duration.
Pricing
Example
Alice purchased an Internetfacing CLB instance whose maximum bandwidth is 2 Mbit/s in the China (Hangzhou) region at 10:00:00 (UTC+8) on January 20, 2022 and changed the maximum bandwidth to 20 Mbit/s at 08:00:00 (UTC+8) on January 21, 2022. Then, Alice released the CLB instance at 12:34:00 (UTC+8) on January 21, 2022. The bandwidth fee is calculated based on the following formula:
Maximum bandwidth on the day when Alice purchased the CLB instance: 2 Mbit/s Maximum bandwidth on the day when Alice modified the maximum bandwidth of the CLB instance: 20 Mbit/s Bandwidth fee for the first day: (2 × 0.006) × 14 = USD 0.168 Bandwidth fee for the next day: [5 × 0.006 + (20  5) × 0.02] × 13 = USD 4.29 Total fee = 0.168 + 4.29 = USD 4.458