Date Format Strings

Quick reference for date/time formatting across popular programming languages.

C# / .NET Format Strings

Standard Date/Time Formats

Custom Format Specifiers

C# Examples

DateTime now = DateTime.Now;

now.ToString("yyyy-MM-dd")           // "2026-01-24"
now.ToString("dd/MM/yyyy")           // "24/01/2026"
now.ToString("MMMM d, yyyy")         // "January 24, 2026"
now.ToString("HH:mm:ss")             // "14:30:45"
now.ToString("h:mm tt")              // "2:30 PM"
now.ToString("yyyy-MM-ddTHH:mm:ss")  // "2026-01-24T14:30:45"
now.ToString("ddd, dd MMM yyyy")     // "Sat, 24 Jan 2026"

JavaScript Date Formatting

Intl.DateTimeFormat Options

toLocaleString() Options

const date = new Date('2026-01-24T14:30:45');

// Short date
date.toLocaleDateString('en-US')
// "1/24/2026"

// Long date
date.toLocaleDateString('en-US', { 
  weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' 
})
// "Saturday, January 24, 2026"

// ISO format
date.toISOString()
// "2026-01-24T14:30:45.000Z"

// Custom formatting
date.toLocaleDateString('en-US', { year: 'numeric', month: '2-digit', day: '2-digit' })
// "01/24/2026"

// Time only
date.toLocaleTimeString('en-US', { hour: '2-digit', minute: '2-digit' })
// "02:30 PM"

Date Methods

Python strftime/strptime

Format Codes

Python Examples

from datetime import datetime

dt = datetime(2026, 1, 24, 14, 30, 45)

dt.strftime('%Y-%m-%d')              # '2026-01-24'
dt.strftime('%d/%m/%Y')              # '24/01/2026'
dt.strftime('%B %d, %Y')             # 'January 24, 2026'
dt.strftime('%H:%M:%S')              # '14:30:45'
dt.strftime('%I:%M %p')              # '02:30 PM'
dt.strftime('%Y-%m-%dT%H:%M:%S')     # '2026-01-24T14:30:45'
dt.strftime('%a, %d %b %Y')          # 'Sat, 24 Jan 2026'

# Parsing
datetime.strptime('2026-01-24', '%Y-%m-%d')
datetime.strptime('24/01/2026 14:30', '%d/%m/%Y %H:%M')

Common Format Patterns