Formatting

The .format() method is very versatile. It accepts a token string or an Intl options object.

Token-based Formatting

Complete Token Reference

Token	Output Example	Description
YYYY	2025	4-digit year
YY	25	2-digit year
MMMM	January	Full month name
MMM	Jan	Abbreviated month name
MM	07	Month, 2-digits (01-12)
M	7	Month (1-12)
DD	09	Day of month, 2-digits (01-31)
D	9	Day of month (1-31)
dddd	Wednesday	Full day of the week name
ddd	Wed	Short day of the week name
dd	We	Minimal day of the week name
d	3	Day of the week, Sunday as 0 (0-6)
HH	14	Hour, 2-digits (00-23)
H	14	Hour (0-23)
hh	02	Hour, 12-hour clock, 2-digits (01-12)
h	2	Hour, 12-hour clock (1-12)
mm	05	Minute, 2-digits (00-59)
m	5	Minute (0-59)
ss	02	Second, 2-digits (00-59)
s	2	Second (0-59)
SSS	123	Millisecond, 3-digits (000-999)
A	PM	AM PM (uppercase)
a	pm	am pm (lowercase)
Z	+02:00	Time zone offset with colon (±HH:mm)
ZZ	+0200	Time zone offset without colon (±HHmm)
z	America/New_York	IANA time zone name

TIP

Use brackets [] to escape literal characters: .format("[Today is] YYYY-MM-DD").

atemporal().format("YYYY-MM-DD [at] HH:mm:ss");
// => "2025-07-09 at 14:23:00"

// Month name and AM/PM examples
atemporal("2024-08-14T16:30:00").format("MMM DD, YYYY");       // "Aug 14, 2024"
atemporal("2024-08-14T16:30:00").format("MMMM Do, hh:mm A");   // "August 14th, 04:30 PM"
atemporal("2024-08-14T16:30:00").format("hh:mm a");             // "04:30 pm"

Intl.DateTimeFormat

For advanced localization, pass an options object.

atemporal().format({ dateStyle: "full", timeStyle: "medium" }, "es-CR");
// => "miércoles, 9 de julio de 2025, 14:23:00"

Any valid Intl.DateTimeFormatOptions works:

// Custom weekday + month + day
atemporal().format({ weekday: "long", month: "long", day: "numeric" }, "ja-JP");
// => "7月9日水曜日"

Advanced Tokens

Additional tokens are available via the advancedFormat plugin:

Token	Output Example	Description	Requires Plugin
Do	15th	Day of month with ordinal suffix	advancedFormat
Qo	3rd	Quarter with ordinal suffix	advancedFormat
zzz	EST	Short localized time zone name	advancedFormat
zzzz	Eastern Standard Time	Long localized time zone name	advancedFormat