Classic Load Balancer (CLB) supports the pay-as-you-go billing method. You can release a pay-as-you-go CLB instance anytime.

Note CLB provides high-performance instances and shared-resource instances. Shared-resource instances are no longer available for purchase. The CLB instances described in this topic refer to high-performance CLB instances.

Billing rules

Item Description
Billing method The pay-as-you-go billing method allows you to use resources before you pay for them. Bills are generated and fees are deducted after each billing cycle.
Scenarios The pay-as-you-go billing method is ideal for the following scenarios:
  • Scenarios in which resource usage fluctuates.
  • Your business has short-term requirements on resource usage.
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 pay-as-you-go CLB instance at 09:30:00 (UTC+8) and release the CLB instance at 12:30:00 (UTC+8), you are charged for 4 hours.
Note If the total amount of your account balance and the 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 of pay-as-you-go CLB instances and whether you can change the metering method.pay-as-go
  • Pay-as-you-go CLB instances support the pay-by-LCU and pay-by-specification metering methods. You can change the metering method as needed. For more information, see Modify the configurations of pay-as-you-go CLB instances.
  • You are charged Internet data transfer fees based on the pay-by-data-transfer or pay-by-bandwidth metering method. CLB allows you to change the metering method as needed.
  • You can change the specification and maximum bandwidth value of a pay-by-specification CLB instance.
For more information, see Change the configuration of a pay-as-you-go 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
  • Pay-by-data-transfer CLB instances: The maximum bandwidth is used for reference only. It indicates the upper limit of the bandwidth. In case of resource contention, the bandwidth allocated to each CLB instance may be lower than its maximum bandwidth value.
  • Pay-by-bandwidth CLB instances: The maximum bandwidth is guaranteed even when resource contention occurs.
For more information, see Bandwidth limits.

Specification fee and LCU fee

Specification fee

You are charged specification fees only for pay-by-specification CLB instances. The following section describes the metrics of high-performance 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.

Click to view the specifications, performance metrics, and prices. The prices listed in the following table are for reference only. The actual prices on the buy page shall prevail.
SpecificationMaximum number of connectionsCPSQPSUnit price in the Chinese mainland and China (Hong Kong) (USD/hour)Unit price outside China (USD/hour)
Specification 1: Small I (slb.s1.small)5000300010000.010.012
Specification 2: Medium I (slb.s2.small)50,0005,0005,0000.050.06
Specification 3: Medium II (slb.s2.medium)100,00010,00010,0000.100.12
Specification 4: Large I (slb.s3.small)200,00020,00020,0000.200.24
Specification 5: Large II (slb.s3.medium)500,00050,00030,0000.310.37
Specification 6: Super Large I (slb.s3.large)1,000,000100,00050,0000.510.61

Example: You purchased an Internet-facing 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 used to measure resources consumed by CLB instances.

LCU usage

CLB charges LCU fees 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 consumed per hour = Max {Number of LCUs based on new connections per hour, Number of LCUs based on concurrent connections per hour, Number of LCUs based on data transfer per hour, Number of LCUs based on rule evaluations per hour}

An LCU measures the dimensions on which CLB processes traffic. The performance metrics of a single LCU vary based on the protocol of CLB listeners.

  • TCP traffic
    MetricDescriptionUnitLCU coefficientCalculation
    Number of new connections (CPS)The number of new TCP connections processed per second. Seconds800The 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. Minute100,000The 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 transferThe data transfer over TCP processed by CLB. Unit: GB. Hour1 GBThe 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
    MetricDescriptionUnitLCU coefficientCalculation
    CPSThe number of new UDP connections processed per second. Seconds400The 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
    CONNSThe number of concurrent UDP connections per minute. Minute50,000The 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 by using the following formula:
    Number of LCUs = Highest CONNS value/LCU coefficient
    Data transferThe data transfer over UDP processed by CLB. Unit: GB. Hour1 GBThe 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
    MetricDescriptionUnitLCU coefficientCalculation
    Number of new connectionsThe number of new HTTP and HTTPS connections processed per second. Seconds25The 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 connectionsThe number of concurrent HTTP and HTTPS connections per minute. Minute3,000The 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 transferThe data transfer over HTTP and HTTPS processed by CLB. Unit: GB. Hour1 GBThe 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 evaluationsThe 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. Seconds1,000The 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 highest number of LCUs consumed on different metrics. The LCU fee of a single CLB instance is the sum of the LCU fees of each listener.

LCU unit price

The number of LCUs consumed each hour is rounded up to the nearest integer.
Note By default, CLB rounds up the hourly LCU consumption to 1 LCU if the value is less than 1 and rounds up the hourly LCU consumption to the nearest integer if the value is not an integer. For example, if the hourly LCU consumption is 0.3, it is rounded up to 1 LCU and you need to pay USD 0.007.
Click to view the LCU unit price. The prices listed in the following table are for reference only. The actual prices on the buy page shall prevail.
Billable itemsLCU unit price (USD/hour per LCU)
LCU0.007

Billing examples

Click to view billing examples.
You created a pay-by-LCU CLB instance in the China (Hangzhou) region at 08:10:00 (UCT+8) on June 8, 2022, and configured TCP and HTTP listeners for the CLB instance. You released the CLB instance at 08:50:00 (UCT+8) on June 8, 2022. The following table describes the highest CPS value, the highest CONNS value, the total 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).
MetricTCPHTTP
CPS (second)The highest CPS value within the hour is 1,600. The number of LCUs is calculated by using the following formula:
1600÷800=2
The highest CPS value within the hour is 100. The number of LCUs is calculated by using the following formula:
100÷25=4
CONNS (minute)The highest CONNS value within the hour is 480,000. The number of LCUs is calculated by using the following formula:
480,000÷100,000=4.8
The highest CONNS value within the hour is 12,000. The number of LCUs is calculated by using the following formula:
12,000÷3,000=4
Data transfer per hourThe data transfer over TCP processed by CLB within the hour is 4 GB. The number of LCUs is calculated by using the following formula:
4÷1=4
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:
3.6÷1=3.6
Number of rule evaluations per second0Assume 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:
(40-25)×400=6,000
The number of LCUs is calculated by using the following formula:
6,000÷1,000=6
In this example, the TCP listener consumes the largest number of LCUs (five LCUs) on concurrent connections. The HTTP listener consumes the largest number of LCUs (six LCUs) on rule evaluations.

The number of LCUs consumed each hour is rounded up to the nearest integer.

LCU fee for the TCP listener = USD 0.007 × 5 = USD 0.035
LCU fee for the HTTP listener = USD 0.007 × 6 = USD 0.042
LCU fee for the CLB instance = LCU fee for the TCP listener + LCU fee for the HTTP listener = USD 0.035 + USD 0.042 = USD 0.077
The average monthly LCU fee for the CLB instance can be calculated by using the following formula: USD 0.077 × 24 × 30 = USD 55.44

Metering methods

Pay-as-you-go CLB instances support the pay-by-LCU and pay-by-specification 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.
Note In the following table, "-" indicates that you are charged the fee and "" indicates that you are not charged the fee.

Network type Metering method for data transmission over the Internet Performance Instance fee Specification fee and LCU fee Fee for data transmission over the Internet
Specification fee LCU fee Data transfer fee Bandwidth fee
Internet-facing Pay-by-data-transfer Determined by the specification that you purchase. The largest specification that you can select is s3.large. - -
Pay-by-bandwidth Determined by the specification that you purchase. The largest specification that you can select is s3.large. - -
Internal-facing - Determined by the specification that you purchase. The largest specification that you can select is s3.large. - - - -
Network type Metering method for data transmission over the Internet Performance Instance fee Specification fee and LCU fee Fee for data transmission over the Internet
Specification fee LCU fee Data transfer fee Bandwidth fee
Internet-facing Pay-by-data-transfer Automatically scales on demand. The upper limit is defined in the s3.large specification. - -
Internal-facing - Automatically scales on demand. The upper limit is defined in the s3.large specification. - - - -

Instance fee

  • Billing description

    You are charged instance fees for CLB on an hourly basis. If you use a CLB instance for less than 1 hour in a billing cycle, 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.

    Note You are not charged instance fees for internal-facing CLB instances.
  • Formula
    Instance fee = Instance unit price (USD/hour) × Usage duration (hours)
  • Pricing
    Click to view the unit prices in different regions. The prices listed in the following table are for reference only. The actual prices on the buy page shall prevail.
    Region Instance unit price (USD/hour)
    China (Hangzhou), China (Shanghai), China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Shenzhen), China (Heyuan), and China (Chengdu) 0.003
    China (Hong Kong), Japan (Tokyo), UAE (Dubai), and South Korea (Seoul) 0.009
    US (Silicon Valley) and US (Virginia) 0.005
    Singapore (Singapore), Malaysia (Kuala Lumpur), Indonesia (Jakarta), India (Mumbai), UK (London), Germany (Frankfurt), Australia (Sydney), and Thailand (Bangkok) 0.006
  • Example
    You purchased an Internet-facing 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

Internet data transfer fee

Data transfer fee (charged for pay-by-data-transfer Internet-facing instances)

  • Billing 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 pay-by-data-transfer Internet-facing 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 one billing cycle:
    Data transfer fee = Unit price of data transfer (USD/GB) × Amount of data transfer (GB)
  • Pricing
    Click to view data transfer unit prices. The prices listed in the following table are for reference only. The actual prices on the buy page shall prevail.
    Region Data transfer unit price (USD/GB)
    China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Shenzhen), and China (Heyuan) 0.125
    China (Qingdao) 0.113
    China (Hong Kong) 0.156
    US (Silicon Valley) and US (Virginia) 0.078
    Malaysia (Kuala Lumpur) 0.112
    Singapore (Singapore), Indonesia (Jakarta), India (Mumbai), and Thailand (Bangkok) 0.117
    Japan (Tokyo) 0.087
    Germany (Frankfurt) and UK (London) 0.070
    UAE (Dubai) 0.447
    Australia (Sydney) 0.096
    South Korea (Seoul) 0.123
  • Example
    You purchased an Internet-facing pay-by-data-transfer 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 pay-by-bandwidth Internet-facing instances)

  • Billing description
    You are charged and billed for pay-by-bandwidth Internet-facing 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. 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 when a CLB instance uses bandwidth.
    • The bandwidth fee of an Internet-facing 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 maximum bandwidth on that day.
    Note

    For pay-by-bandwidth 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
    Click to view bandwidth unit prices. The prices listed in the following table are for reference only. The actual prices on the buy page shall prevail.
    Region Unit price of bandwidth from 1 to 5 Mbit/s (USD/hour) Unit price of bandwidth from 1 to 5 Mbit/s (USD/day) Unit price of bandwidth higher than 5 Mbit/s (USD/hour) Unit price of bandwidth higher than 5 Mbit/s (USD/day)
    China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Shenzhen), China (Heyuan), and China (Chengdu) 0.006 0.144 0.02 0.48
    China (Qingdao) 0.005 0.12 0.016 0.384
    China (Hong Kong) 0.006 0.144 0.02 0.48
    Singapore (Singapore), Indonesia (Jakarta), India (Mumbai), Malaysia (Kuala Lumpur), Germany (Frankfurt), UK (London), Australia (Sydney), Thailand (Bangkok), and South Korea (Seoul) 0.006 0.144 0.02 0.48
    Japan (Tokyo) 0.007 0.168 0.023 0.552
    UAE (Dubai) 0.048 11.52 0.118 2.832
    US (Silicon Valley) and US (Virginia) 0.006 0.144 0.02 0.48
  • Example
    You purchased a 2 Mbit/s Internet-facing 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 fees are calculated by using the following formulas:
    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 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