Date.now() returns the current number of milliseconds since the Unix epoch without creating a Date object. This guide covers syntax, timing patterns, seconds conversion, and how it compares to getTime().
Date.now()
On Date
Large integer
Start / end
Same value
Unix seconds
Measuring how long code takes, stamping log entries, and generating client-side timestamps all need the current time as a number. JavaScript provides Date.now()—a static method that returns epoch milliseconds directly, with no new Date() required.
It is the most common shortcut for “what time is it right now?” in milliseconds. To read the timestamp from an existing Date instance, use getTime() instead.
Date.now() MethodDate.now() is a static method on the Date constructor. You call it as Date.now(), not on a date instance. It returns the same millisecond value as new Date().getTime().
The result counts milliseconds since January 1, 1970 00:00:00 UTC. That value is timezone-independent—everyone on Earth gets the same number at the same instant.
Prefer Date.now() over new Date().getTime() when you only need the current timestamp—it avoids creating an object you never use.
Date.now()NaN).| Goal | Code |
|---|---|
| Current timestamp (ms) | Date.now() |
| Unix seconds | Math.floor(Date.now() / 1000) |
| Elapsed milliseconds | Date.now() - start |
| Equivalent instance call | new Date().getTime() |
| Date from timestamp | new Date(Date.now()) |
| Deadline check | Date.now() > deadlineMs |
These APIs involve time but serve different jobs. Pick the one that matches your task.
now msStatic current time
epoch msOn a Date instance
same msCoercion hook
elapsedHigh-res benchmark
Open DevTools Console (F12) or use Try-it links. Timestamps from “now” will differ on your machine—that is expected.
Read the current epoch milliseconds with one static call.
Call Date.now() to read milliseconds since the Unix epoch.
const timestamp = Date.now();
console.log("Timestamp (ms):", timestamp);The number grows every millisecond. Store it in a variable when you need to compare or subtract later.
Seconds conversion, timing, logging, and API comparison.
Many APIs expect whole seconds, not milliseconds. Divide by 1000 and floor the result.
const unixSeconds = Math.floor(Date.now() / 1000);
console.log("Unix seconds:", unixSeconds);Date.now() is always in milliseconds. Dividing by 1000 drops the sub-second fraction for second-granularity APIs.
Record a start timestamp, run work, then subtract to get elapsed milliseconds.
const start = Date.now();
// Simulated work
let sum = 0;
for (let i = 0; i < 100000; i++) sum += i;
const elapsed = Date.now() - start;
console.log("Elapsed:", elapsed, "ms");Subtracting two Date.now() values gives elapsed wall-clock milliseconds. For sub-millisecond browser benchmarks, consider performance.now().
Attach Date.now() to events for simple client-side logging.
function logEvent(message) {
const entry = { at: Date.now(), message };
console.log(JSON.stringify(entry));
}
logEvent("User clicked Save");Epoch milliseconds sort chronologically as numbers. For human-readable logs, convert with new Date(entry.at).toISOString().
Date.now() and getTime()Both read the current instant—they should match when called back-to-back.
const fromNow = Date.now();
const fromGetTime = new Date().getTime();
console.log("Date.now():", fromNow);
console.log("getTime():", fromGetTime);
console.log("Equal:", fromNow === fromGetTime);They usually match when called in the same millisecond. If a tick passes between calls, values can differ by 1 ms—that is normal.
Date.now() to a stored deadline.Date.now() Returns the Current TimeYou invoke Date.now() on the constructor, not an instance.
The engine reads the current wall-clock instant from the host.
Milliseconds since Jan 1, 1970 00:00:00 UTC are computed.
Subtract, compare, store, or pass to new Date(ms).
Date.now() returns milliseconds, not seconds.Date instance.new Date().getTime() but avoids object allocation.performance.now() may be more precise.crypto.randomUUID().Date.now() has been available since ES5 (2009). It works in every modern browser and all Node.js versions.
Supported in Chrome, Firefox, Safari, Edge, Internet Explorer 9+, and all Node.js versions. No polyfill required.
Bottom line: Safe everywhere. Remember milliseconds, not seconds, and prefer it over new Date().getTime() for current time.
Date.now() is the simplest way to read the current Unix timestamp in JavaScript. Use it for timing, deadlines, and logging; convert to seconds when APIs require it; and reach for getTime() when you already have a Date object.
Next, learn Date.parse() to turn date strings into timestamps, or review getTime() for instance-based reads.
Date.now() directly for current time< and >new Date() only to call getTime()getSeconds() (0–59 clock part)Date.now()Your foundation for current timestamps in JavaScript.
Date.now()
On Date.
TypeSince 1970.
Unitend - start.
PatternUnix sec.
ConvertDate.now() and new Date().getTime() return the same millisecond value—but only Date.now() skips creating a Date object you never use.
Learn how to parse date strings into epoch milliseconds.
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