---
title: Date.prototype.setFullYear()
short-title: setFullYear()
slug: Web/JavaScript/Reference/Global_Objects/Date/setFullYear
page-type: javascript-instance-method
browser-compat: javascript.builtins.Date.setFullYear
sidebar: jsref
---

The **`setFullYear()`** method of {{jsxref("Date")}} instances changes the year, month, and/or day of month for this date according to local time.

{{InteractiveExample("JavaScript Demo: Date.prototype.setFullYear()")}}

```js interactive-example
const event = new Date("August 19, 1975 23:15:30");

event.setFullYear(1969);

console.log(event.getFullYear());
// Expected output: 1969

event.setFullYear(0);

console.log(event.getFullYear());
// Expected output: 0
```

## Syntax

```js-nolint
setFullYear(yearValue)
setFullYear(yearValue, monthValue)
setFullYear(yearValue, monthValue, dateValue)
```

### Parameters

- `yearValue`
  - : An integer representing the year. For example, 1995.
- `monthValue` {{optional_inline}}
  - : An integer representing the month: 0 for January, 1 for February, and so on.
- `dateValue` {{optional_inline}}
  - : An integer between 1 and 31 representing the day of the month. If you specify `dateValue`, you must also specify `monthValue`.

### Return value

Changes the {{jsxref("Date")}} object in place, and returns its new [timestamp](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#the_epoch_timestamps_and_invalid_date). If a parameter is `NaN` (or other values that get [coerced](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number#number_coercion) to `NaN`, such as `undefined`), the date is set to [Invalid Date](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#the_epoch_timestamps_and_invalid_date) and `NaN` is returned.

## Description

If you do not specify the `monthValue` and `dateValue` parameters, the same values as what are returned by {{jsxref("Date/getMonth", "getMonth()")}} and {{jsxref("Date/getDate", "getDate()")}} are used.

If a parameter you specify is outside of the expected range, other parameters and the date information in the {{jsxref("Date")}} object are updated accordingly. For example, if you specify 15 for `monthValue`, the year is incremented by 1 (`yearValue + 1`), and 3 is used for the month.

Because `setFullYear()` operates on the local time, crossing a Daylight Saving Time (DST) boundary may result in a different elapsed time than expected. For example, if setting the date crosses a spring-forward transition (losing an hour), the difference in timestamps between the new and old date is one hour less than the nominal day difference multiplied by 24 hours. Conversely, crossing a fall-back transition (gaining an hour) result in an extra hour. If you need to adjust the date by a fixed amount of time, consider using {{jsxref("Date/setUTCFullYear", "setUTCFullYear()")}} or {{jsxref("Date/setTime", "setTime()")}}.

If the new local time falls within an offset transition, the exact time is derived using the same behavior as `Temporal`'s [`disambiguation: "compatible"`](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal/ZonedDateTime#ambiguity_and_gaps_from_local_time_to_utc_time) option. That is, if the local time corresponds to two instants, the earlier one is chosen; if the local time does not exist (there is a gap), we go forward by the gap duration.

## Examples

### Using setFullYear()

```js
const theBigDay = new Date();
theBigDay.setFullYear(1997);
```

## Specifications

{{Specifications}}

## Browser compatibility

{{Compat}}

## See also

- {{jsxref("Date.prototype.getUTCFullYear()")}}
- {{jsxref("Date.prototype.setUTCFullYear()")}}
- {{jsxref("Date.prototype.setYear()")}}