# Handlebars Helper Function: dateAdd

Adds or subtracts a specific amount of time to a date. Use this helper to perform date arithmetic such as adding days to a date, subtracting months, or adjusting hours and minutes.

## Availability

This helper is available in the Summer ’26 release of Marketing Cloud Next.

## Syntax

```handlebars
{{dateAdd date number interval}}
```

## Parameters

| Parameter  | Type              | Description                                                                                                                                                           |
| ---------- | ----------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `date`     | String or Object  | Required. The starting date.                                                                                                                                          |
| `number`   | Integer or String | Required. The amount of time to add. Use a negative value to subtract time from `date`. If you specify a string, the helper function tries to convert it to a number. |
| `interval` | String            | Required. The time unit to add or subtract. Possible values: `"Y"` (year), `"M"` (month), `"D"` (day), `"H"` (hour), `"MI"` (minute), `"S"` (second).                 |

You can specify `date` in these formats:

- **US formats**: `MM/dd/yyyy`, `M/d/yyyy`, `MM/dd/yyyy HH:mm:ss`, `M/d/yyyy h:mm a`, or `M/d/yyyy h:mm:ss a`

- **ISO formats**: `yyyy-MM-dd`, `yyyy-MM-dd HH:mm:ss`, `yyyy-MM-dd'T'HH:mm:ss`, or `yyyy-MM-dd'T'HH:mm:ss.SSSZ`

- **12-hour time**: `M/d/yyyy h:mm a`, `yyyy-MM-dd h:mm a`, or `yyyy-MM-dd h:mm:ss a`

- **Time-only**: `h:mm a` or `h:mm:ss a`

  :::note
  If you specify only a time, the helper function uses the current date.
  :::

- **Long-form English**: `d MMMM yyyy`, `MMMM d, yyyy`, or `EEEE, MMMM d, yyyy`

- **Chinese and Japanese notation**: `yyyy年M月d日`

- **Korean notation**: `yyyy년 M월 d일` or `yyyy년M월d일`

## Return Value

The function returns a date-time string in the format `yyyy-MM-dd HH:mm:ss`.

If the value of the `date` parameter is February 29th during a leap year, the helper uses February 28th to perform calculations. For example, `{{dateAdd "2024-02-29" 1 "Y"}}` returns `2025-02-28 00:00:00`.

## See Also

- [DateDiff](/handlebars/reference/date-time/mcn-handlebars-reference-date-time-datediff.html)
- [Now](/handlebars/reference/date-time/mcn-handlebars-reference-date-time-now.html)
- [TimezoneConversion](/handlebars/reference/date-time/mcn-handlebars-reference-date-time-timezoneconversion.html)