References

Beginner-friendly references for web development, with live, editable examples.

The JavaScript Date object

Object JavaScript All modern browsers Updated
Quick answer

The Date object represents a single moment in time. Create one with new Date() for now, or pass a date string or numbers. Read parts with getFullYear(), getHours() and so on, and format with toLocaleDateString(). Watch the classic gotcha: months are zero-based, so January is 0.

Overview

The Date object handles dates and times. new Date() captures the current moment; new Date("2026-06-23") parses a date string; and new Date(year, month, day) builds one from parts. Internally a date is just a number — milliseconds since January 1, 1970 (the "Unix epoch") — which you can read with getTime().

You read the pieces with getter methods: getFullYear(), getMonth(), getDate() (day of the month), getDay() (day of the week), getHours(), getMinutes(). For display, the toLocale* methods are your friends — toLocaleDateString() and toLocaleTimeString() format a date according to the user's locale, which is far better than building strings by hand.

Two gotchas bite everyone. First, months are zero-based: getMonth() returns 0 for January and 11 for December, and the same when constructing — new Date(2026, 0, 1) is January 1st. (Confusingly, getDate() for the day is one-based.) Second, the native Date API is famously clunky for parsing and arithmetic, so for heavy date work many developers reach for the modern Temporal API or a library like date-fns.

Syntax

const now = new Date();                  // current date & time
const d = new Date("2026-06-23");        // from a string
const d2 = new Date(2026, 5, 23);        // June 23 (month is 0-based!)

now.getFullYear();          // e.g. 2026
now.getMonth();             // 0-11 (0 = January)
now.toLocaleDateString();   // locale-formatted

Example

Live example 
<pre id="out" style="font:15px ui-monospace,monospace"></pre>
<script>
  const now = new Date();

  document.getElementById('out').textContent =
    'year:  ' + now.getFullYear() + '\n' +
    'month: ' + (now.getMonth() + 1) + '  (getMonth is 0-based)\n' +
    'local: ' + now.toLocaleDateString();
</script>

Best practices

  • Remember months are zero-based: 0 is January, 11 is December.
  • Format for display with toLocaleDateString() / toLocaleTimeString() rather than building strings manually.
  • Use getTime() (milliseconds) to compare or subtract dates.
  • For heavy parsing or date math, consider the modern Temporal API or a library like date-fns.

Frequently asked questions

How do I get the current date in JavaScript?
Use new Date(), which represents the current date and time.
Why is getMonth() off by one?
Months are zero-based: getMonth() returns 0 for January through 11 for December. Add 1 for the human month number.
How do I format a date nicely?
Use date.toLocaleDateString() or toLocaleString(), which format according to the user's locale.
How do I compare two dates?
Compare their getTime() values (milliseconds), or subtract them: (d2 - d1) gives the difference in milliseconds.
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