---
title: ipPrefix
description: |
  Return the CIDR subnet for a given IP address and subnet size.
url: https://coralogix.com/docs/dataprime/language-reference/functions-reference/ip/ipprefix/
product: dataengine
feature: DataPrime Language
feature_id: dataprime-language
feature_identifier: dataengine/dataprime-language
last_updated: '2026-10-21'
---

# `ipPrefix`

## Description

Return the CIDR subnet for a given IP address and subnet size.

## Syntax

Like many functions in DataPrime, `ipPrefix` supports<!-- --> [two notations](https://coralogix.com/docs/dataprime/language-reference/functions-reference.md),<!-- --> **function** and **method**. These interchangeable forms allow flexibility in how you structure expressions.

* Function notation
* Method notation

```
ipPrefix(ip: string, subnetSize: number): string
```

```
(ip: string).ipPrefix(subnetSize: number): string
```

## Arguments

| Name         | Type     | Required | Description                                                              |
| ------------ | -------- | -------- | ------------------------------------------------------------------------ |
| `ip`         | `string` | **true** | The IP address to process                                                |
| `subnetSize` | `number` | **true** | Number of mask bits in the subnet, e.g. `10` produces a `/10` CIDR range |

## Example

**Use case: Derive the subnet from an IP address**

Compute the subnet for a given IP when the number of mask bits is known.

### Example data

```
{

    "ip": "155.123.7.4"

}
```

### Example query

* Function notation
* Method notation

```
create ip_subnet from ipPrefix(ip, 10)
```

```
create ip_subnet from ip.ipPrefix(10)
```

### Example output

```
{

    "ip": "155.123.7.4",

    "ip_subnet": "155.64.0.0/10"

}
```