> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/welcome/pricing/elastic-compute-billing/load-balancer-billing.md).

# Load Balancer Billing

## Prerequisites

* Load balancer resources are all [**pay-as-you-go**](/welcome/pricing/general-pricing-rules/pay-as-you-go.md) resources charged by hour, with a minimum of one hour price. Please first see [**General Pricing Rules**](/welcome/pricing/general-pricing-rules.md) and [**General Lifecycle Rules**](/welcome/pricing/general-lifecycle-rules.md) to know about basic pricing ways of pay-as-you-go resources.
* Load Balancer currently includes the following pricing items: instance fees, LCU fees, elastic IP fees, and public data transfer fees.

{% hint style="info" %} <mark style="color:blue;">**Note**</mark>

<mark style="color:blue;">The actual price varies in different locations and zones, therefore the price shown on the order page shall prevail.</mark>
{% endhint %}

## Billing Items

### Load Balance Instance

The billing method of the load balancer is [**Pay-as-you-go**](/welcome/pricing/general-pricing-rules/pay-as-you-go.md). You pay for your resources afterward by hour.

### LCU

An LCU (Load Balancer Capacity Unit) is the smallest unit used to measure resources consumed by a load balancer. The number of LCUs is determined by the higher value between concurrent connections per minute and new connections per second (CPS), and further affected by the LCU coefficient. It also varies based on the protocols of listeners.

**Metrics**

* **Concurrent Connections**\
  Concurrent Connections refer to the number of connections that are active and being handled simultaneously by a load balancing instance at a given time (per minutes).
* **CPS**\
  Connections Per Second (CPS) refers to the number of new connections that a load balancing instance can handle in one second.

**Protocols**

* **TCP**\
  TCP, Transmission Control Protocol, is reliable and ensures all data arrives correctly and in order, making it ideal for web browsing, emails, and file transfers.
* **UDP**\
  UDP, User Datagram Protocol, is faster but less reliable, as it doesn’t guarantee delivery or order—perfect for streaming, online games, and real-time communication where speed matters more than accuracy.

**LCU Coefficient**

To calculate the number of LCUs, divide the higher value between concurrent connections per minute and CPS by the corresponding coefficient based on the protocol type.

<table><thead><tr><th width="281.70703125">Metric</th><th>TCP</th><th>UDP</th></tr></thead><tbody><tr><td>Concurrent Connections</td><td>100,000</td><td>50,000</td></tr><tr><td>CPS</td><td>800</td><td>400</td></tr></tbody></table>

#### **LCU Fee Formula**

> * LCU fee = LCU unit price (USD/LCU) × Number of LCUs per hour × Duration (hours)
>
> * Number of LCUs per hour = max {Number of LCUs for concurrent connections, Number of LCUs for CPS}
>
> > Number of LCUs for concurrent connections = Highest concurrent connections value/LCU coefficient
> >
> > Number of LCUs for CPS = Highest CPS value/LCU coefficient

#### LCU Billing Example

You create a pay-as-you-go load balancer with a TCP listener and a UDP listener. You release it after one hour. The following table describes the highest concurrent connections value, the highest CPS value, and the total amount of data transfer during this period.

<table><thead><tr><th width="164.15625">Metric</th><th>TCP Listener</th><th>UDP Listener</th></tr></thead><tbody><tr><td>Concurrent Connections</td><td><p>The highest value within the hour is 550,000.</p><p>Number of LCUs = 550,000/100,000 = 5.5</p></td><td><p>The highest value within the hour is 350,000.</p><p>Number of LCUs = 350,000/100,000 = 3.5</p></td></tr><tr><td>CPS</td><td><p>The highest value within the hour is 2,400.</p><p>Number of LCUs = 2,400/800 = 3.0</p></td><td><p>The highest value within the hour is 1,600.</p><p>Number of LCUs = 1,600/800 = 2.0</p></td></tr></tbody></table>

The Number of LCUs:

* For TCP listener per hour\
  \= max {Number of LCUs for concurrent connections, Number of LCUs for CPS}\
  \= Number of LCUs for concurrent connections\
  \= 5.5
* For UDP listener per hour\
  \= max {Number of LCUs for concurrent connections, Number of LCUs for CPS}\
  \= Number of LCUs for concurrent connections\
  \= 3.5

Assume the LCU unit price is $0.02/h, then your LCU fee will be:

* LCU fee\
  \= LCU unit price (USD/LCU) × Number of LCUs per hour × Duration (hours)\
  \= $0.02/LCU/h × (5.5 LCUs + 3.5 LCUs) × 1 h\
  \= $0.18

### Elastic IP

Elastic IP billing is based on usage time (hourly) and the number of IPs. Please refer to the order page for exact pricing.

### Public Data Transfer

Public network fees can be billed by data transfer or flat rate. View [Data Transfer](/welcome/pricing/network-billing/data-transfer.md) and [Flat Rate](/welcome/pricing/network-billing/flat-rate.md) for more details.