CLB: Pay-as-you-go billing - Server Load Balancer - Alibaba Cloud Documentation Center

Classic Load Balancer (CLB) supports pay-as-you-go. This includes pay-by-usage and pay-by-specification (discontinued). You can release pay-as-you-go instances at any time.

Note

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 pay-as-you-go CLB instances:
- Instance fee is renamed public IP retention fee.
- A billable item instance fee is added.
For more information, see CLB billing adjustments.
Starting at 00:00:00 on June 1, 2025 (Beijing Time, UTC+8), Alibaba Cloud will discontinue offering new pay-by-specification CLB instances. For details, see the Announcement on the Discontinuation of Pay-by-Specification Classic Load Balancer (CLB) Instances.

Pay-as-you-go

Feature	Description
Billing description	Pay-as-you-go is a post-paid billing method where you pay for resources after you use them. At the end of each billing cycle, we issue a bill and deduct the fees from your account.
Use cases	Pay-as-you-go is ideal for the following scenarios: Frequent fluctuations in business usage. Temporary or bursty resource needs.
Billing cycle	Pay-as-you-go fees are settled hourly on the hour (UTC+8). A new billing cycle starts after each settlement. If you use a resource for less than one hour in a billing cycle, you are billed for one full hour. For example, if you create a pay-as-you-go CLB instance at 09:30:00 and release it at 12:30:00, the billable period is from 09:00:00 to 13:00:00, for a total of 4 billable hours. Note If your available credit (your Alibaba Cloud account balance and coupons) cannot cover your outstanding bill, we will notify you by SMS or email.

Instance billing methods

The pay-as-you-go option for CLB has two billing methods: pay-by-usage and pay-by-specification (discontinued). The billable items, instance network type, and public IP address billing type vary by billing method.

Note

In the following tables, a hyphen (-) indicates that the item is not charged, and a checkmark (✔) indicates that it is charged.

Pay-by-usage

Instance network type	Public IP address billing type	Maximum instance performance	Instance fee	Public IP address fee	LCU and specification fee		Public network fee
Instance network type	Public IP address billing type	Maximum instance performance	Instance fee	Public IP address fee	LCU fee	Specification fee	Data transfer fee	Bandwidth fee
Public network	Pay-by-data-transfer	Automatically scales based on usage. For the upper limit, see maximum instance performance.	✔	✔	✔	-	✔	-
Private network	-	Automatically scales based on usage. For the upper limit, see maximum instance performance.	✔		✔	-	-	-

Pay-by-specification (Discontinued)

Instance network type	Public IP address billing type	Maximum instance performance	Instance fee	Public IP address fee	LCU and specification fee		Public network fee
Instance network type	Public IP address billing type	Maximum instance performance	Instance fee	Public IP address fee	LCU fee	Specification fee	Data transfer fee	Bandwidth fee
Public network	Pay-by-data-transfer	Determined by the purchased specification. The maximum available specification is s3.large.	✔	✔	-	✔	✔	-
Public network	Pay-by-bandwidth	Determined by the purchased specification. The maximum available specification is s3.large.	✔	✔	-	✔	-	✔
Private network	-	Determined by the purchased specification. The maximum available specification is s3.large.	✔		-	✔	-	-

Important

Pay-as-you-go private network instances do not incur a public IP address fee, data transfer fee, or bandwidth fee. If you associate a separately purchased EIP with a private network CLB instance, the public network fees incurred by the EIP are billed for the EIP and do not appear on the CLB bill.
Data transfer between a CLB instance and backend ECS instances within the same region is free of charge.

Instance fee

The instance fee is the base charge for a CLB instance. You are charged this fee as long as your instance exists and has not been released. This fee applies to all Pay-As-You-Go instances.

The billing cycle for the CLB instance fee is 1 hour. Usage for less than one hour within a billing cycle is billed as a full hour. The billing duration is the period from instance creation to its release.

instance fee = instance unit price (USD/hour) × billing duration (hours), where the instance unit price is "USD 0.021/hour".

Note

Instance fees are waived for CLB instances created before 00:00:00 on December 1, 2024. This waiver is valid until 23:59:59 on November 30, 2026. For more information, see Notice on Extending the Validity Period of the Discount on Instance Fees for Classic Load Balancer (CLB).

Public IP retention fee

The public IP retention fee is charged for retaining a public IP address for a Classic Load Balancer (CLB). This fee is incurred as long as the public IP address exists, regardless of its usage status. This fee applies only to pay-as-you-go instances.

The public IP retention fee is calculated based on the unit price of the public IP address, the billing duration, and the number of instances.

Public IP Retention Fee = Public IP Address Unit Price × Billing Duration × Number of Instances

The following tables show the unit prices. The regions and prices in these tables are for reference only. For the actual prices, refer to the purchase page.

Region	Instance fee (USD/instance/hour)
China (Hangzhou), China (Shanghai), China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Chengdu), China (Ulanqab)	0.003
China (Hong Kong), Japan (Tokyo), UAE (Dubai), Korea (Seoul)	0.009
US (Silicon Valley), US (Virginia), Mexico (Mexico City)	0.005
Philippines (Manila), Singapore, Malaysia (Kuala Lumpur), Indonesia (Jakarta), UK (London), Germany (Frankfurt), Thailand (Bangkok)	0.006
Saudi Arabia (Riyadh)	0.008

LCU and specification fee

LCU fees

A Load Balancer Capacity Unit (LCU) is the smallest unit for measuring the resources consumed by a load balancer. LCU fees are performance charges for pay-as-you-go CLB instances, settled hourly based on actual usage. Only pay-as-you-go instances incur LCU fees.

Instance performance limit

The performance of pay-as-you-go instances scales automatically with your usage, and LCU fees are charged hourly based on the resources you consume. The performance limits are shown in the following table.

Metric	Maximum connections	New connections per second (CPS)	Queries per second (QPS)
instance performance limit	1,000,000	100,000	50,000

LCU usage

LCU fees are charged hourly. If you use a resource for less than a full hour, you are billed for the entire hour.

Hourly LCU fees = LCU price (USD/LCU) × Number of LCUs per hour

Number of LCUs per hour = max{Number of LCUs for new connections, Number of LCUs for concurrent connections, Number of LCUs for data transfer, Number of LCUs for rule evaluations}

A Load Balancer Capacity Unit (LCU) is a performance metric that measures the traffic processed by a CLB instance. The performance metrics included in a single LCU depend on the protocol used by the CLB listener.

For TCP traffic

Metric	Description	Metering interval	LCU factor	Hourly LCU calculation
New connections	The number of new TCP connections processed per second.	Second	800	The number of LCUs for new connections is calculated from the peak number of new TCP connections per second recorded within the billing cycle. The formula is as follows: `Number of LCUs = Maximum new connections / LCU factor`
Concurrent connections	The number of concurrent TCP connections per minute.	Minute	100,000	The number of LCUs for concurrent connections is calculated from the peak number of concurrent TCP connections per minute recorded within the billing cycle. The formula is as follows: `Number of LCUs = Maximum concurrent connections / LCU factor`
Data transfer	The volume of data from TCP requests and responses processed by CLB, in GB.	Hour	1 GB	The number of LCUs for data transfer is calculated from the total volume of data from TCP requests and responses processed within the billing cycle. The formula is as follows: `Number of LCUs = Total data transfer / LCU factor`

For UDP traffic

Metric	Description	Metering interval	LCU factor	Hourly LCU calculation
New connections	The number of new UDP connections processed per second.	Second	400	The number of LCUs for new connections is calculated from the peak number of new UDP connections per second recorded within the billing cycle. The formula is as follows: `Number of LCUs = Maximum new connections / LCU factor`
Concurrent connections	The number of concurrent UDP connections per minute.	Minute	50,000	The number of LCUs for concurrent connections is calculated from the peak number of concurrent UDP connections per minute recorded within the billing cycle. The formula is as follows: `Number of LCUs = Maximum concurrent connections / LCU factor`
Data transfer	The volume of data from UDP requests and responses processed by CLB, in GB.	Hour	1 GB	The number of LCUs for data transfer is calculated from the total volume of data from UDP requests and responses processed within the billing cycle. The formula is as follows: `Number of LCUs = Total data transfer / LCU factor`

For HTTP(S) traffic

Metric	Description	Metering interval	LCU factor	Hourly LCU calculation
New connections	The number of new HTTP(S) connections processed per second.	Second	25	The number of LCUs for new connections is calculated from the peak number of new HTTP(S) connections per second recorded within the billing cycle. The formula is as follows: `Number of LCUs = Maximum new connections / LCU factor`
Concurrent connections	The number of concurrent HTTP(S) connections per minute.	Minute	3,000	The number of LCUs for concurrent connections is calculated from the peak number of concurrent HTTP(S) connections per minute recorded within the billing cycle. The formula is as follows: `Number of LCUs = Maximum concurrent connections / LCU factor`
Data transfer	The volume of data from HTTP(S) requests and responses processed by CLB, in GB.	Hour	1 GB	The number of LCUs for data transfer is calculated from the total volume of data from HTTP(S) requests and responses processed within the billing cycle. The formula is as follows: `Number of LCUs = Total data transfer / LCU factor`
Rule evaluations	This value is the number of processed forwarding rules multiplied by the queries per second (QPS). The first 25 forwarding rules are free of charge. If the number of forwarding rules processed is greater than 25, rule evaluations = QPS × (Number of forwarding rules processed - 25). If the number of forwarding rules processed is 25 or less, the value for rule evaluations is zero.		1,000	The number of LCUs is calculated by dividing the number of rule evaluations by the LCU factor. The number of rule evaluations is calculated based on the peak QPS recorded within the billing cycle. The formula is as follows: `Number of LCUs = Rule evaluations / LCU factor`

The number of LCUs consumed by each listener per hour is calculated based on the preceding metrics. You are billed based on the metric with the highest LCU usage. The total LCU fee for a CLB instance is the sum of the LCU fees for all its listeners.

LCU price

The LCU price is USD 0.007/LCU/hour. For the actual price, refer to the buy page.

For a given hour, after each metric is converted to LCUs, the LCU consumption is calculated based on actual usage, with a minimum precision of 0.000001 LCU. For example, if you consume 0.1 LCUs in an hour, the LCU fee for that hour is 0.1 × 0.007 = USD 0.0007.

LCU billing example

Suppose you create a pay-as-you-go CLB instance in the China (Hangzhou) region at 08:10:00 on June 8, 2022. You configure a TCP listener and an HTTP listener for the instance, and then release it at 08:50:00 on the same day. The following table shows the sample data for the 08:00–09:00 billing cycle.

Metric	TCP	HTTP
New connections (per second)	Peak new TCP connections for the hour: 1,600. LCU conversion: `1600/800 = 2`	Peak new HTTP connections for the hour: 100. LCU conversion: `100/25 = 4`
Concurrent connections (per minute)	Peak concurrent TCP connections for the hour: 480,000. LCU conversion: `480,000/100,000 = 4.8`	Peak concurrent HTTP connections for the hour: 12,000. LCU conversion: `12,000/3,000 = 4`
Data transfer (per hour)	TCP request and response data processed during the hour: 4 GB. LCU conversion: `4/1 = 4`	HTTP request and response data processed during the hour: 3.6 GB. LCU conversion: `3.6/1 = 3.6`
Rule evaluations (per second)	0	Assume that the HTTP listener is configured with 40 forwarding rules and the peak request rate is 400 QPS. Because the number of forwarding rules exceeds the free quota, the peak rule evaluations for the hour are calculated as follows: `(40 - 25) × 400 = 6,000` LCU conversion: `6,000/1,000 = 6`

For the TCP listener, the metric with the highest LCU usage is concurrent connections (4.8 LCUs). For the HTTP listener, it is rule evaluations (6 LCUs).

LCU fee for the TCP listener = USD 0.007/LCU × 4.8 LCUs = USD 0.0336
LCU fee for the HTTP listener = USD 0.007/LCU × 6 LCUs = USD 0.042
Total LCU fee for the CLB instance for the hour = LCU fee for the TCP listener + LCU fee for the HTTP listener = USD 0.0336 + USD 0.042 = USD 0.0756
Based on this usage, the estimated monthly LCU fee for the CLB instance is approximately: USD 0.0756 × 24 hours × 30 days = USD 54.432

Estimate LCU consumption

You can use the LCU calculator to estimate LCU consumption for a CLB instance.

Specification fee

The specification fee is a fixed charge for pay-by-specification CLB instances. This fee is based on the selected specification and does not vary with usage. This fee only applies to pay-as-you-go instances that use the pay-by-specification billing method.

A performance-guaranteed instance has the following three key performance metrics. These metrics vary by instance specification. For more information, see Performance-guaranteed Instance FAQ.

Maximum connections is the maximum number of concurrent connections that a CLB instance can handle. If the number of connections on the instance exceeds the specification's limit, new connection requests are dropped.
New connections per second (CPS) is the rate at which new connections can be established. If this rate exceeds the specification's limit, new connection requests are dropped.
Queries per second (QPS) is a metric for layer 7 listeners that measures the number of HTTP(S) requests processed per second. If the request rate exceeds the specification's QPS limit, new requests are dropped.

The following table details the instance specifications, their load-balancing capabilities, and reference pricing. The actual price is shown on the purchase page.

Specification	Maximum connections	CPS	QPS	Unit price (China)	Unit price (Overseas)
Entry I (slb.s1.small)	5,000	3,000	1,000	0.01	0.012
Standard I (slb.s2.small)	50,000	5,000	5,000	0.05	0.06
Standard II (slb.s2.medium)	100,000	10,000	10,000	0.10	0.12
Advanced I (slb.s3.small)	200,000	20,000	20,000	0.20	0.24
Advanced II (slb.s3.medium)	500,000	50,000	30,000	0.31	0.37
Super I (slb.s3.large)	1,000,000	100,000	50,000	0.51	0.61

Example: If you create a public instance with the Standard I (slb.s2.small) specification in the China (Hangzhou) region at 10:00:00 on November 20, 2021, and then release it at 12:34:00 on November 21, 2021, the fee is calculated as follows:

Specification unit price for a Standard I (slb.s2.small) instance in the China (Hangzhou) region = USD 0.05/hour
Billing duration = 27 hours
Specification fee = USD 0.05/hour × 27 hours = USD 1.35

Public network fee

Data transfer fee

Data transfer fees are charged for outbound data transfer (downlink traffic). Inbound data transfer (uplink traffic) is free. These fees apply only to public CLB instances that use the pay-by-data-transfer billing method.

Important

For pay-by-data-transfer public CLB instances, the maximum bandwidth is not guaranteed. It is a reference and a cap. Your bandwidth may be throttled during periods of resource contention. For more information, see Bandwidth throttling.

For pay-by-data-transfer public CLB instances, both the billing cycle and the settlement cycle are one hour. If you use an instance for less than one hour within a billing cycle, we charge you for the full hour.

Data transfer fee = Unit price of data transfer (USD/GB) × Data transfer (GB)

The following table lists the unit prices for data transfer. The listed prices are for reference only. The prices on the buy page are final.

Region	Unit price (USD/GB)
China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Ulanqab)	0.125
China (Qingdao)	0.113
China (Hong Kong)	0.156
US (Silicon Valley), US (Virginia)	0.078
Malaysia (Kuala Lumpur)	0.112
Philippines (Manila), Singapore, Indonesia (Jakarta), Thailand (Bangkok)	0.117
Japan (Tokyo)	0.087
Germany (Frankfurt), UK (London)	0.070
Mexico (Mexico City)	0.078
UAE (Dubai)	0.447
South Korea (Seoul)	0.123
Saudi Arabia (Riyadh)	0.141

Example: Suppose you create a pay-by-data-transfer public CLB instance in the China (Hangzhou) region at 10:00:00 on November 20, 2021, and then release it at 12:34:00 on November 21, 2021. During this period, the instance consumes a total of 5 GB of outbound data transfer. The fee is calculated as follows:

Unit price of data transfer in the China (Hangzhou) region = USD 0.125/GB
Data transfer = 5 GB
Data transfer fee = USD 0.125/GB × 5 GB = USD 0.625

Bandwidth fee

The bandwidth fee is a charge for the provisioned bandwidth of a public CLB instance billed by fixed bandwidth. This is a fixed fee based on the bandwidth you purchase and is unaffected by actual data transfer. This fee applies only to pay-as-you-go public instances billed by fixed bandwidth.

Important

For public CLB instances that are billed by fixed bandwidth (part of the discontinued pay-by-specification model), the peak bandwidth is a guaranteed performance metric, even during periods of resource contention. For more information, see Bandwidth limits.

Public CLB instances billed by fixed bandwidth have a one-day billing cycle. Within a billing cycle, if you use an instance for less than one hour, you are billed for one full hour. If the instance runs for less than a full day, the fee is calculated based on the actual hours of use for that day. The billable duration is the time the instance operates with fixed bandwidth.

The bandwidth unit price for public CLB instances billed by fixed bandwidth is tiered, with a threshold at 5 Mbps.
If you make a bandwidth change within a billing cycle, CLB calculates the bandwidth fee based on the highest peak bandwidth recorded for that day.

Note

For instances billed by bandwidth, the peak inbound bandwidth is the same as the peak outbound bandwidth.

For peak bandwidth from 1 to 5 Mbps: Bandwidth fee = Peak bandwidth × Unit price × Billing duration
For peak bandwidth greater than 5 Mbps: Bandwidth fee = [5 × (Unit price for 1-5 Mbps) + (Peak bandwidth - 5) × (Unit price for >5 Mbps)] × Billing duration

The following tables list the unit prices for bandwidth. The listed regions and prices are for reference only. The price on the purchase page is final.

Region	Hourly price (1–5 Mbps)	Daily price (1–5 Mbps)	Hourly price (>5 Mbps)	Daily price (>5 Mbps)
China (Hangzhou), China (Shanghai), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Shenzhen), China (Heyuan), 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), Malaysia (Kuala Lumpur), Germany (Frankfurt), UK (London), Thailand (Bangkok), 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), US (Virginia), Mexico (Queretaro)	0.006	0.144	0.02	0.48

Example: Assume you create a public CLB instance with 2 Mbps of bandwidth in the China (Hangzhou) region at 10:00:00 on November 20, 2021. You change the bandwidth to 20 Mbps at 08:00:00 on November 21, 2021, and then release the instance at 12:34:00 on November 21, 2021. The fees are calculated as follows:

Peak bandwidth on Day 1 = 2 Mbps
Peak bandwidth on Day 2 = 20 Mbps
Bandwidth fee for Day 1 = (2 × 0.006) × 14 = USD 0.168
Bandwidth fee for Day 2 = [5 × 0.006 + (20 - 5) × 0.02] × 13 = USD 4.29
Total bandwidth fee = 0.168 + 4.29 = USD 4.458

Change the billing method

This section describes the billing methods and configuration changes for pay-as-you-go CLB instances.

The pay-as-you-go instance billing method includes pay-by-usage and pay-by-specification (discontinued). You can convert a pay-by-specification instance to a pay-by-usage instance, but not vice versa. For more information, see Change the billing method of a pay-as-you-go instance.
For a pay-by-specification instance, you can change the instance specification, internet charge type, and bandwidth value.
Changes that do not involve the internet charge type take effect immediately. Otherwise, all configuration changes for the instance take effect at 00:00:00 on the following day. You cannot make other configuration changes until the pending changes take effect.

Cost optimization

Cost reduction

Fee type	Actions
public network traffic fee	Purchase a Data Transfer Plan to offset public network traffic fees.
specification fee	For pay-by-specification instances, adjust the instance specification to your business needs to prevent resource waste.
idle resources	Promptly release unused CLB instances and public IP addresses to prevent unnecessary charges. Release EIPs bound to internal-facing CLB instances separately.
additional discounts	After applying savings options like resource plans and Data Transfer Plans, contact your account manager to ask about further discounts on your CLB costs.

Cost estimation

Use the CLB LCU Estimator to estimate your LCU consumption.
Estimate future costs based on past bills and projected business growth.

Troubleshoot sudden cost increases

Use the CloudMonitor console to view trends in metrics like traffic and request counts for your CLB instances to identify when the cost increase occurred.
Review CLB access logs (which must be enabled in advance) and backend server logs to check for abnormal traffic or malicious attacks.
In the Billing Management console, compare your current bill with historical bills to identify the specific billable items that have increased.
Set up cost alerts to receive notifications when your costs exceed a predefined threshold. This helps you detect anomalies quickly.