Date .toLocaleDateString() / toISOString()

Methods for converting a Date object to a human-readable string. You can display dates in a locale-specific format or convert to ISO format.

Syntax

// Returns a locale-specific date string.
var str = date.toLocaleDateString();
var str = date.toLocaleDateString(locale, options);

// Returns a locale-specific date and time string.
var str = date.toLocaleString();

// Returns a locale-specific time string.
var str = date.toLocaleTimeString();

// Returns a string in ISO 8601 format.
var str = date.toISOString();

Method List

Method	Description
date.toLocaleDateString()	Returns a locale-specific date string. In a US English environment, this produces a format like "4/15/2025".
date.toLocaleString()	Returns a locale-specific date and time string.
date.toLocaleTimeString()	Returns a locale-specific time string.
date.toISOString()	Returns a string in ISO 8601 format. The time zone is always UTC.
date.toDateString()	Returns a short English date string, such as "Tue Apr 15 2025".

Sample Code

var date = new Date(2025, 3, 15, 14, 30, 45); // April 15, 2025, 14:30:45

// Basic conversions
console.log(date.toLocaleDateString()); // Outputs something like "4/15/2025".
console.log(date.toLocaleString()); // Outputs something like "4/15/2025, 2:30:45 PM".
console.log(date.toLocaleTimeString()); // Outputs something like "2:30:45 PM".
console.log(date.toISOString()); // Outputs "2025-04-15T05:30:45.000Z". Converted to UTC.
console.log(date.toDateString()); // Outputs "Tue Apr 15 2025".

// Display the date with a specific locale.
console.log(date.toLocaleDateString("ja-JP")); // Outputs "2025/4/15".
console.log(date.toLocaleDateString("en-US")); // Outputs "4/15/2025".
console.log(date.toLocaleDateString("de-DE")); // Outputs "15.4.2025".

// Use options to control the display format in detail.
var options = {
	year: "numeric",
	month: "long",
	day: "numeric",
	weekday: "long"
};
console.log(date.toLocaleDateString("ja-JP", options)); // Outputs "2025年4月15日火曜日".
console.log(date.toLocaleDateString("en-US", options)); // Outputs "Tuesday, April 15, 2025".

// Specify time formatting options.
var timeOptions = {
	hour: "2-digit",
	minute: "2-digit",
	hour12: false
};
console.log(date.toLocaleTimeString("en-US", timeOptions)); // Outputs "14:30".

Common Options

Option	Values	Description
year	"numeric" / "2-digit"	Format for the year. "numeric" displays 4 digits; "2-digit" displays the last 2 digits.
month	"numeric" / "2-digit" / "long" / "short"	Format for the month. "long" displays the full name (e.g., "April"); "short" displays an abbreviated name (e.g., "Apr").
day	"numeric" / "2-digit"	Format for the day of the month.
weekday	"long" / "short" / "narrow"	Format for the day of the week. "long" displays the full name (e.g., "Tuesday"); "short" displays an abbreviated name (e.g., "Tue").
hour / minute / second	"numeric" / "2-digit"	Format for the hour, minute, and second.
hour12	true / false	Specifies whether to use 12-hour time. Set to false for 24-hour time.

Notes

Choose the appropriate string conversion method based on your use case. When displaying a date to the user, date.toLocaleDateString() is convenient because it respects the user's locale. You can pass a locale string as the first argument and an options object as the second argument to control the output format precisely.

date.toISOString() returns a string in ISO 8601 format, making it suitable for API communication and data storage. Note that the time zone is always converted to UTC — for example, 14:00 in Japan (JST) becomes 05:00 in UTC (9 hours behind).

If you need to build a custom date format, use getter methods such as 'date.getFullYear()'.