Best JavaScript Date Libraries in 2026: date-fns vs Day.js vs Luxon

TL;DR

date-fns for functional, tree-shakeable date utilities. Day.js as a lightweight Moment.js drop-in. Luxon for timezone-heavy applications. Moment.js is dead — stopped adding features in 2020 and recommends migrating away. The right choice in 2026 depends on your bundle size requirements and timezone needs.

Key Takeaways

date-fns: ~40M weekly downloads — most popular post-Moment choice
Day.js: ~25M downloads — smallest bundle, Moment.js compatible API
Luxon: ~12M downloads — best timezone handling, Intl-based
Moment.js: declining — in legacy maintenance mode
Temporal API coming — browser-native, but not widely available yet

The Options

date-fns — Functional & Tree-Shakeable

import { format, addDays, differenceInDays, parseISO, isWithinInterval } from 'date-fns';
import { formatInTimeZone } from 'date-fns-tz';

// Only imports what you use — ideal for bundling
const now = new Date();
format(now, 'yyyy-MM-dd'); // '2026-03-08'
format(now, 'MMMM d, yyyy'); // 'March 8, 2026'

addDays(now, 7); // Date 7 days from now
differenceInDays(new Date('2026-04-01'), now); // Days until April 1

// Parse ISO strings
const date = parseISO('2026-03-08T10:30:00');

// Timezone formatting (date-fns-tz)
formatInTimeZone(now, 'America/New_York', 'yyyy-MM-dd HH:mm zzz');
// '2026-03-08 05:30 EST'

Bundle: ~13KB for common operations (tree-shakeable) Best for: Functional style, TypeScript projects, webpack/Vite bundling

Day.js — Smallest Bundle

import dayjs from 'dayjs';
import relativeTime from 'dayjs/plugin/relativeTime';
import timezone from 'dayjs/plugin/timezone';
import utc from 'dayjs/plugin/utc';

dayjs.extend(relativeTime);
dayjs.extend(utc);
dayjs.extend(timezone);

// Moment.js-compatible chainable API
dayjs('2026-03-08').format('MMMM D, YYYY'); // 'March 8, 2026'
dayjs().add(7, 'days').format('YYYY-MM-DD');
dayjs('2020-01-01').from('2026-01-01'); // '6 years ago'

// Timezone
dayjs().tz('America/New_York').format('HH:mm'); // '05:30'

Bundle: ~2KB base + ~3KB per plugin Best for: Moment.js migration, bundle size constraints

Luxon — Best Timezone Support

import { DateTime, Duration, Interval } from 'luxon';

// Rich timezone support via Intl API
const dt = DateTime.now().setZone('America/New_York');
dt.toFormat('yyyy-MM-dd HH:mm ZZZZ'); // '2026-03-08 05:30 Eastern Standard Time'
dt.zoneName; // 'America/New_York'
dt.offset;   // -300

// Duration math
const dur = Duration.fromObject({ months: 1, days: 3 });
DateTime.now().plus(dur).toISO();

// Intervals
const interval = Interval.fromDateTimes(
  DateTime.local(2026, 1, 1),
  DateTime.local(2026, 12, 31)
);
interval.count('days'); // 364

Bundle: ~23KB gzipped Best for: Complex timezone handling, international applications

Comparison Table

Feature	date-fns	Day.js	Luxon	Moment.js
Downloads (wk)	40M	25M	12M	15M (legacy)
Bundle size	~13KB*	~2KB	~23KB	~72KB
Immutable	✓ (functions)	✓	✓	✗
Timezone	Plugin (date-fns-tz)	Plugin	Native (Intl)	Plugin
TypeScript	✓	✓	✓	@types/moment
Tree-shakeable	✓✓	✓	✓	✗
Maintenance	Active	Active	Active	Maintenance-only

*date-fns tree-shakes to only imported functions

The Temporal API

// Temporal — upcoming browser-native date API
// Proposal stage 3, polyfill available
import { Temporal } from '@js-temporal/polyfill';

const date = Temporal.Now.plainDateISO();
console.log(date.toString()); // '2026-03-08'

const datetime = Temporal.Now.zonedDateTimeISO('America/New_York');
datetime.add({ days: 7 }).toString();

// Better timezone support than any library
// Immutable by design
// Not yet in most browsers — use polyfill for now

Temporal is the future, but not ready for production without a polyfill (~100KB).

Recommendations

Use Case	Pick
New TypeScript project	date-fns
Migrating from Moment.js	Day.js (API compatible)
Timezone-heavy international app	Luxon
Minimum bundle, CDN delivery	Day.js
Relative time ("3 hours ago")	Day.js (built-in plugin) or date-fns
Future-proof	Wait for Temporal + use polyfill now

Compare date library health scores on PkgPulse.