JavaScript Date Set Methods

JavaScript Date objects don’t just let you get parts of a date — you can also set or modify them.

These are called Date Set Methods, and they help you update a date’s year, month, day, hour, minute, second, or even milliseconds.

Using these methods, you can easily create dynamic dates, schedule events, or adjust times based on user input or time zones.

setFullYear() – Set the Year

The setFullYear() method in JavaScript is used to set or update the year of a Date object. Optionally, you can also set the month (0 for January, 11 for December) and the day of the month.

Syntax:

date.setFullYear(yearValue, monthValue, dayValue)

Example:

const d = new Date();
d.setFullYear(2025);
console.log(d);
// Wed Oct 08 2025 ...

setMonth() – Set the Month

Changes the month of the date object (0-indexed). Months are zero-based (0–11). You can optionally set the day of the month.

Syntax:

date.setMonth(monthValue, dayValue)

Example:

const d = new Date("2025-10-08");
d.setMonth(0); // January (0 = Jan)
console.log(d);
// Wed Jan 08 2025 ...

setDate() – Set the Day of the Month

Sets the day of the month for the date object (1–31).

Syntax:

date.setDate(dayValue)

Example:

const d = new Date("2025-10-08");
d.setDate(15);
console.log(d);
// Wed Oct 15 2025 ...

setHours() – Set the Hour

Sets the hours (0–23) for the date object. You can also set minutes, seconds, and milliseconds optionally.

Syntax:

date.setHours(hoursValue, minutesValue, secondsValue, msValue)

Example:

const d = new Date("2025-10-08T10:00:00");
d.setHours(18);
console.log(d);
// Wed Oct 08 2025 18:00:00

setMinutes() – Set the Minutes

Sets the minutes (0–59) of the date object. You can also set seconds and milliseconds.

Syntax:

date.setMinutes(minutesValue, secondsValue, msValue)

Example:

const d = new Date("2025-10-08T18:00:00");
d.setMinutes(45);
console.log(d);
// Wed Oct 08 2025 18:45:00

setSeconds() – Set the Seconds

Sets the seconds (0–59) of the date object. You can also set milliseconds optionally.

Syntax:

date.setSeconds(secondsValue, msValue)

Example:

const d = new Date("2025-10-08T18:30:00");
d.setSeconds(50);
console.log(d);
// Wed Oct 08 2025 18:30:50

setMilliseconds() – Set the Milliseconds

Sets the milliseconds (0–999) of a date object.

Syntax:

date.setMilliseconds(msValue)

Example:

const d = new Date("2025-10-08T18:30:45.000");
d.setMilliseconds(500);
console.log(d);
// 2025-10-08T18:30:45.500

setTime() – Set Timestamp

Sets the date and time using a Unix timestamp (milliseconds since Jan 1, 1970).

Syntax:

date.setTime(milliseconds)

Example:

const d = new Date();
d.setTime(1759917000000);
console.log(d);
// Wed Oct 08 2025 18:30:00

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