# MOM_REL
URL: https://docs.valsight.ai/mom-rel/
Description: Returns the relative month-over-month growth (percentage change) between the current and previous month. Missing months can be skipped or treated as zero, depending on the selected behavior.
**Category:** [Compare periods](/compare-periods/)

## Overview

The **MOM\_REL** function **returns the relative growth for each month compared to the previous month** (month-over-month).

Use this function when you need the percentage change between consecutive months.

## Syntax

`MOM_REL('Node' [, "MissingValueBehaviour"])`

## Parameters

| Parameter                 | Description                                                                  | Type           | Required | Default            |
| ------------------------- | ---------------------------------------------------------------------------- | -------------- | -------- | ------------------ |
| **Node**                  | Input node, specified using the node name in single quotes (e.g. `'Profit'`) | Node reference | Yes      | --                 |
| **MissingValueBehaviour** | How missing values are treated.                                              | Keyword        | No       | `"IGNORE_MISSING"` |

**MissingValueBehaviour options:**

* `"IGNORE_MISSING"`: Missing rows are skipped. This is the default.
* `"MISSING_AS_ZERO"`: Missing rows are treated as 0.

## Examples

### Default: ignoring missing values

This example shows MOM\_REL with the default behavior. The missing months are skipped and no result is produced for them.

**Input node:** `'Profit'`

| Month   | Value |
| ------- | ----- |
| 2025-01 | 200   |
| 2025-02 | 300   |
| 2025-03 | 450   |
| 2025-04 | 500   |
| 2026-02 | 100   |

**Formula:** `MOM_REL('Profit')`

**Equivalent to:** `MOM_REL('Profit', "IGNORE_MISSING")`

| Month   | Calculation       | Result |
| ------- | ----------------- | ------ |
| 2025-02 | (300 - 200) / 200 | 0.5    |
| 2025-03 | 150 / 300         | 0.5    |
| 2025-04 | 50 / 450          | 0.11   |

### Treating missing values as zero

With MISSING\_AS\_ZERO, gaps are filled with 0, producing results for every month including those without input data.

**Formula:** `MOM_REL('Profit', "MISSING_AS_ZERO")`

| Month   | Calculation       | Result |
| ------- | ----------------- | ------ |
| 2025-02 | (300 - 200) / 200 | 0.5    |
| 2025-03 | 150 / 300         | 0.5    |
| 2025-04 | 50 / 450          | 0.11   |
| 2025-05 | (0 - 500) / 500   | -1     |
| 2026-03 | (0 - 100) / 100   | -1     |

2026-02 is not present in the result: even with MISSING\_AS\_ZERO, dividing by a zero previous value causes a division by zero, so the entry is dropped.

## Related

| Function                  | When to use instead                                                             |
| ------------------------- | ------------------------------------------------------------------------------- |
| [MOM\_ABS](/mom-abs/)     | When you need the absolute difference month-over-month instead of a percentage. |
| [YOY\_REL](/yoy-rel/)     | When you need the percentage change on a yearly basis instead of monthly.       |
| [DELTA\_REL](/delta-rel/) | When you need relative change along any dimension, not just time.               |