Date & Time Functions Guide

Last updated: October 12, 2025

Date & Time Functions Guide

Format dates and timestamps in your document templates with powerful formatting options.

Table of Contents

  • dateFormat Function
  • Date Format Layouts
  • Common Date Patterns
  • Real-World Examples

dateFormat Function

The dateFormat function converts date strings into formatted output using Go's date layout patterns.

Basic Syntax

{{dateFormat .DateField "layout"}}

Supported Input Formats

The function automatically parses these input formats:

  • RFC3339: 2025-09-21T15:30:00Z
  • Date only: 2025-09-21
  • DateTime: 2025-09-21T15:30:00

Example:

<p>Date: {{dateFormat .InvoiceDate "January 2, 2006"}}</p>

Sample Data:

{
  "InvoiceDate": "2025-09-21"
}

Output:

<p>Date: September 21, 2025</p>

Date Format Layouts

Go uses a reference date/time to specify formats: Mon Jan 2 15:04:05 MST 2006

Basic Components

  • 2006: Four-digit year
  • 06: Two-digit year
  • January: Full month name
  • Jan: Abbreviated month (3 letters)
  • 01: Two-digit month (01-12)
  • 1: Month without leading zero
  • 02: Two-digit day (01-31)
  • 2: Day without leading zero
  • Monday: Full weekday name
  • Mon: Abbreviated weekday

Time Components

  • 03: Two-digit hour (01-12)
  • 3: Hour without leading zero
  • 15: Two-digit hour (00-23)
  • 04: Two-digit minute (00-59)
  • 4: Minute without leading zero
  • 05: Two-digit second (00-59)
  • 5: Second without leading zero
  • PM: Uppercase AM/PM
  • pm: Lowercase am/pm
  • MST: Timezone abbreviation
  • -0700: Timezone offset

Common Date Patterns

Full Date Formats

<!-- Long Format: September 21, 2025 -->
{{dateFormat .Date "January 2, 2006"}}

<!-- Medium Format: Sep 21, 2025 -->
{{dateFormat .Date "Jan 2, 2006"}}

<!-- Short Format: 09/21/2025 -->
{{dateFormat .Date "01/02/2006"}}

<!-- ISO Format: 2025-09-21 -->
{{dateFormat .Date "2006-01-02"}}

<!-- European Format: 21/09/2025 -->
{{dateFormat .Date "02/01/2006"}}

<!-- With Weekday: Sunday, September 21, 2025 -->
{{dateFormat .Date "Monday, January 2, 2006"}}

<!-- Abbreviated: Sun, Sep 21, 2025 -->
{{dateFormat .Date "Mon, Jan 2, 2006"}}

Real-World Examples

Example 1: Invoice Header

<div class="invoice-header">
  <h1>INVOICE</h1>
  <div class="invoice-info">
    <p><strong>Invoice Number:</strong> {{.InvoiceNumber}}</p>
    <p><strong>Invoice Date:</strong> {{dateFormat .InvoiceDate "January 2, 2006"}}</p>
    <p><strong>Due Date:</strong> {{dateFormat .DueDate "January 2, 2006"}}</p>
    <p><strong>Issued:</strong> {{dateFormat .IssuedDateTime "Jan 2, 2006 at 3:04 PM"}}</p>
  </div>
</div>

Date Format Cheat Sheet

Quick Reference

  • 2006: Year (four digits)
  • 06: Year (two digits)
  • January: Month (full name)
  • Jan: Month (abbreviated)
  • 01: Month (two digits)
  • 1: Month (no leading zero)
  • 02: Day (two digits)
  • 2: Day (no leading zero)
  • Monday: Weekday (full name)
  • Mon: Weekday (abbreviated)
  • 15: Hour (24-hour, two digits)
  • 03: Hour (12-hour, two digits)
  • 3: Hour (12-hour, no leading zero)
  • 04: Minute (two digits)
  • 4: Minute (no leading zero)
  • 05: Second (two digits)
  • 5: Second (no leading zero)
  • PM: AM/PM (uppercase)
  • pm: AM/PM (lowercase)
  • MST: Timezone (abbreviation)
  • -0700: Timezone (numeric offset)

Common Layouts

  • "2006-01-02" → 2025-09-21
  • "01/02/2006" → 09/21/2025
  • "02/01/2006" → 21/09/2025
  • "January 2, 2006" → September 21, 2025
  • "Jan 2, 2006" → Sep 21, 2025
  • "Monday, January 2, 2006" → Sunday, September 21, 2025
  • "Mon, Jan 2, 2006" → Sun, Sep 21, 2025
  • "15:04" → 15:30
  • "3:04 PM" → 3:30 PM
  • "2006-01-02 15:04:05" → 2025-09-21 15:30:45
  • "Jan 2, 2006 at 3:04 PM" → Sep 21, 2025 at 3:30 PM

Best Practices

  • Be Consistent: Use the same date format throughout a document.
  • Consider Audience: Use regional formats appropriate for your users.
  • Include Timezone: For time-sensitive documents, include timezone information.
  • Use Full Dates: For legal documents, use full date formats (e.g., "January 2, 2006").
  • Test Edge Cases: Verify formatting with dates at month/year boundaries.

Troubleshooting

Date Not Formatting?

Check that your input date is in one of these formats:

  • RFC3339: 2025-09-21T15:30:00Z
  • Date: 2025-09-21
  • DateTime: 2025-09-21T15:30:00

Wrong Output?

Remember Go's reference date: January 2, 2006 at 3:04:05 PM

  • Use 01 for month, not MM
  • Use 02 for day, not DD
  • Use 2006 for year, not YYYY
Quick Tip: The reference date is Mon Jan 2 15:04:05 MST 2006 - a memorable sequence: 1/2 3:04:05 2006!
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