Classic Load Balancer (CLB) supports the payasyougo billing method. You can release a payasyougo CLB instance anytime.
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 rule  The payasyougo billing method allows you to use resources before you pay for them. Bills are generated and fees are deducted after each billing cycle. 
Scenario  The payasyougo billing method is ideal for the following scenarios:

Billing cycle  Fees are calculated on an hourly basis (UTC+8). After fees are calculated, 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 change  The following figure describes the metering methods and configuration changes of payasyougo CLB instances:
For more information, see Change the configuration of a payasyougo CLB instance. 
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. 
Maximum bandwidth 
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.
Formula
Instance fee = Instance unit price (USD/hour) × Duration of usage (hours)
Pricing
Example
You 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 by using 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 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: You 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 by using 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/LCU) × Number of LCUs consumed per hour
Number of LCUs per hour = max {Number of LCUs based on new connections, Number of LCUs based on concurrent connections, Number of LCUs based on data transfer, Number of LCUs based on rule evaluations}
LCUs are used to measure the performance when CLB processes traffic. The performance metrics of an LCU vary with the protocol of a CLB listener.
TCP traffic
Metric
Description
Unit
LCU coefficient
Calculation
CPS
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 highest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula:
Number of LCUs = Highest CPS value/LCU coefficient
Number of concurrent connections (CONNS)
The number of concurrent TCP connections per minute.
Minute
100,000
The system collects all CONNS values within a billing cycle and then divides the highest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula:
Number of LCUs = Highest CONNS value/LCU coefficient
Data transfer
The data transfer over TCP that is processed by
CLB
. Unit: GB.Hour
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 by using the following formula:
Number of LCUs = Total amount of data transfer/LCU coefficient
UDP traffic
Metric
Description
Unit
LCU coefficient
Calculation
CPS
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 highest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula:
Number of LCUs = Highest CPS value/LCU coefficient
CONNS
The number of concurrent UDP connections per minute.
Minute
50,000
The system collects all CONNS values within a billing cycle and then divides the highest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula:
Number of LCUs = Highest CONNS value/LCU coefficient
Data transfer
The data transfer over UDP that is processed by CLB. Unit: GB.
Hour
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 by using the following formula:
Number of LCUs = Total amount of data transfer/LCU coefficient
HTTP and HTTPS traffic
Metric
Description
Unit
LCU coefficient
Calculation
CPS
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 highest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula:
Number of LCUs = Highest CPS value/LCU coefficient
CONNS
The number of concurrent HTTP and HTTPS connections per minute.
Minute
3,000
The system collects all CONNS values within a billing cycle and then divides the highest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula:
Number of LCUs = Highest CONNS value/LCU coefficient
Data transfer
The data transfer over HTTP and HTTPS that is processed by CLB. Unit: GB.
Hour
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 by using 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). You can use 25 forwarding rules free of charge. If the number of forwarding rules processed by CLB is greater than 25, the following formula is applied: 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 is applied: 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 highest 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 by using 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 price
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 provided for reference only. For more information about the actual prices, visit the buy page.
Billable item  Unit price of LCUs (USD/LCU/hour) 
LCU  0.007 
Example
You 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. You released the instance at 08:50:00 (UTC+8) on June 8, 2022. The following table describes the highest CPS value, the highest 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 (second)  The highest CPS value within the hour is 1,600. The number of LCUs is calculated by using the following formula:
 The highest CPS value within the hour is 100. The number of LCUs is calculated by using the following formula:

CONNS (minute)  The highest CONNS value within the hour is 480,000. The number of LCUs is calculated by using the following formula:
 The highest CONNS value within the hour is 12,000. The number of LCUs is calculated by using the following formula:

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

Number of rule evaluations (second)  0  Assume that 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 by using the following formula:
The number of LCUs is calculated by using 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.
Formula
Within a billing cycle: Data transfer fee = Unit price of data transfer (USD/GB) × Amount of data transfer (GB)
Pricing
Example
You 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 is less than 1 hour in a billing cycle, the usage duration is rounded up to 1 hour. If the usage duration is less than one day, you are charged for 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.
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
You purchased a 2 Mbit/s Internetfacing CLB instance 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, you released the CLB instance at 12:34:00 (UTC+8) on January 21, 2022. The bandwidth fee is calculated by using the following formula:
Maximum bandwidth on the day when you purchased the CLB instance: 2 Mbit/s Maximum bandwidth on the day when you 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