Time Formatting / Parsing

Go supports time formatting and parsing via pattern-based layouts. Instead of codes like %Y, a layout is the reference time Mon Jan 2 15:04:05 MST 2006, written the way you want your times to look.

package main

import (
	"fmt"
	"time"
)

func main() {
	p := fmt.Println

Here's a basic example of formatting a time according to RFC3339, using the corresponding layout constant.

	t := time.Date(2026, time.October, 18, 15, 4, 5, 123456789, time.UTC)
	p(t.Format(time.RFC3339))

Time parsing uses the same layout values as Format.

	t1, e := time.Parse(
		time.RFC3339,
		"2012-11-01T22:08:41+00:00")
	p(t1)

Format and Parse use example-based layouts. Usually you'll use a constant from time for these layouts, but you can also supply custom layouts. Layouts must use the reference time Mon Jan 2 15:04:05 MST 2006 to show the pattern with which to format or parse a given time or string. The example time must be as shown: the year 2006, 15 for the hour, Monday for the day of the week, etc.

	p(t.Format("3:04PM"))
	p(t.Format("Mon Jan _2 15:04:05 2006"))
	p(t.Format("2006-01-02T15:04:05.999999-07:00"))
	form := "3 04 PM"
	t2, e := time.Parse(form, "8 41 PM")
	p(t2)

Common layouts have names: DateOnly, TimeOnly, DateTime, and Kitchen.

	p(t.Format(time.DateOnly), t.Format(time.TimeOnly), t.Format(time.Kitchen))

For purely numeric representations you can also use standard string formatting with the extracted components of the time value.

	fmt.Printf("%d-%02d-%02dT%02d:%02d:%02d-00:00\n",
		t.Year(), t.Month(), t.Day(),
		t.Hour(), t.Minute(), t.Second())

Parse will return an error on malformed input explaining the parsing problem.

	ansic := "Mon Jan _2 15:04:05 2006"
	_, e = time.Parse(ansic, "8:41PM")
	p(e)

ParseInLocation reads a time that has no zone in a given location.

	loc := time.FixedZone("UTC+2", 2*60*60)
	t3, _ := time.ParseInLocation(time.DateTime, "2026-10-18 09:30:00", loc)
	p(t3, t3.UTC())
}

$ go run ./66_time_formatting_parsing
2026-10-18T15:04:05Z
2012-11-01 22:08:41 +0000 UTC
3:04PM
Sun Oct 18 15:04:05 2026
2026-10-18T15:04:05.123456+00:00
0000-01-01 20:41:00 +0000 UTC
2026-10-18 15:04:05 3:04PM
2026-10-18T15:04:05-00:00
parsing time "8:41PM" as "Mon Jan _2 15:04:05 2006": cannot parse "8:41PM" as "Mon"
2026-10-18 09:30:00 +0200 UTC+2 2026-10-18 07:30:00 +0000 UTC

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