Frequently Asked Questions

Common questions about the Kurdish Calendar library.

General Questions

What is the Kurdish Calendar?

The Kurdish calendar is a solar calendar based on the Solar Hijri system, with Nowruz (spring equinox) marking the new year. It consists of 12 months with the first 6 months having 31 days, months 7-11 having 30 days, and month 12 having 29 or 30 days in leap years.

What year is it in the Kurdish calendar?

The Kurdish calendar epoch is approximately 700 BCE (founding of the Median Empire). To convert:

When is Nowruz?

Nowruz occurs at the spring equinox:

The exact date can vary by location due to time zones and longitude.

Library Usage

Should I use KurdishDate or KurdishAstronomicalDate?

Use KurdishDate (simplified) for:

Use KurdishAstronomicalDate for:

How accurate is the astronomical calculation?

The astronomical calculation is accurate to ±1 minute for years 1800-2200, validated against published ephemeris data from Fred Espenak (www.Astropixels.com).

Which dialect should I use?

Region Recommended Dialect
Iraqi Kurdistan Sorani or Kurmanji
Iran Sorani
Turkey Kurmanji
Syrian Kurdistan Kurmanji
Hawraman region Hawrami

Choose based on your target audience’s preferences.

Which script should I use?

Context Recommended Script
Iraq (official) Arabic or Latin (both common)
Iraq (modern apps) Latin (increasingly common)
Iran Arabic (primarily)
Turkey Latin (primarily)
Syria Arabic or Latin
Diaspora Latin (primarily)

Allow users to choose their preferred script when possible.

Date Conversion

Why does my date differ by one day?

This can happen when:

  1. Simplified vs Astronomical: Simplified uses fixed 21 March; astronomical uses actual equinox (can be 19-22 March)
// Simplified: Always 21 March
KurdishDate simplified = new KurdishDate(2725, 1, 1);
Console.WriteLine(simplified.ToDateTime()); // 2025-03-21

// Astronomical: Actual equinox (might be 20 March)
KurdishAstronomicalDate astro = KurdishAstronomicalDate.FromErbil(2725, 1, 1);
Console.WriteLine(astro.ToDateTime()); // 2025-03-20
  1. Time zones: The equinox occurs at a specific UTC moment, but the calendar date depends on local time zone

How do I convert between Kurdish and Gregorian?

// Kurdish → Gregorian
KurdishDate kurdish = new KurdishDate(2725, 6, 15);
DateTime gregorian = kurdish.ToDateTime();

// Gregorian → Kurdish
DateTime gregorian = new DateTime(2025, 9, 6);
KurdishDate kurdish = KurdishDate.FromDateTime(gregorian);

Can I convert to/from other calendar systems?

The library converts to/from Gregorian. For other calendar systems (Islamic, Hebrew, etc.), convert via Gregorian as an intermediate step:

// Kurdish → Gregorian → Other calendar
KurdishDate kurdish = new KurdishDate(2725, 1, 1);
DateTime gregorian = kurdish.ToDateTime();
// Use .NET or third-party library for other calendars

Formatting and Parsing

How do I format dates in different languages?

KurdishDate date = new KurdishDate(2725, 1, 1);

// Sorani Latin
date.ToString("D", KurdishDialect.SoraniLatin);
// Output: "1 Xakelêwe 2725"

// Sorani Arabic
date.ToString("D", KurdishDialect.SoraniArabic);
// Output: "١ خاکەلێوە ٢٧٢٥"

// Kurmanji Latin
date.ToString("D", KurdishDialect.KurmanjiLatin);
// Output: "1 Xakelêwe 2725"

// Hawrami Latin
date.ToString("D", KurdishDialect.HawramiLatin);
// Output: "1 Newroz 2725"

What format strings are supported?

Standard formats:

Custom formats using tokens:

See Formatting Guide for complete details.

How do I parse user input?

Use TryParse for safe parsing:

string userInput = GetUserInput();

if (KurdishDate.TryParse(userInput, KurdishDialect.SoraniLatin, out KurdishDate date))
{
  Console.WriteLine($"Valid date: {date}");
}
else
{
  Console.WriteLine("Invalid date format");
}

Why doesn’t my date parse?

Common issues:

  1. Wrong dialect: Ensure dialect matches input
  2. Invalid separator: Use /, -, or space (not . or ,)
  3. Wrong format: Supported formats are dd/MM/yyyy or dd MonthName yyyy
  4. Case sensitivity: Month names are case-insensitive, but must match dialect

Leap Years

How are leap years determined?

Simplified (33-year cycle): Leap years occur at positions 1, 5, 9, 13, 17, 22, 26, 30 in each 33-year cycle.

Astronomical: Year is leap if there are 366 days between consecutive Nowruz dates.

Do simplified and astronomical leap years match?

Usually yes, but occasionally they differ:

int year = 2725;

KurdishDate simplified = new KurdishDate(year, 1, 1);
Console.WriteLine($"Simplified leap: {simplified.IsLeapYear}");

KurdishAstronomicalDate astro = KurdishAstronomicalDate.FromErbil(year, 1, 1);
Console.WriteLine($"Astronomical leap: {astro.IsLeapYear}");

// Usually match, but can differ in edge cases

Performance

Which is faster: KurdishDate or KurdishAstronomicalDate?

KurdishDate (Simplified):

KurdishAstronomicalDate:

For most applications, the difference is negligible.

Should I cache dates?

Date types are lightweight value types (structs). Create them as needed rather than caching:

// Good - Create when needed
KurdishDate GetBirthday() 
{
  return new KurdishDate(2700, 5, 15);
}

// Unnecessary - No need to cache
private static readonly KurdishDate _birthday = new KurdishDate(2700, 5, 15);

Astronomical dates have internal equinox caching, so you don’t need to cache the dates themselves.

Gregorian Dates with Kurdish Names

What’s the difference between Kurdish calendar and Gregorian with Kurdish names?

Kurdish Calendar:

Gregorian with Kurdish Names:

DateTime gregorian = new DateTime(2025, 1, 15);

// Gregorian with Kurdish names
string formatted = gregorian.ToSoraniGregorian();
// Output: "15 Kanûnî Duhem 2025" (January 15, 2025)

// Kurdish calendar
KurdishDate kurdish = KurdishDate.FromDateTime(gregorian);
Console.WriteLine(kurdish.ToString("D", KurdishDialect.SoraniLatin));
// Output: "26 Befranbar 2724" (Different date entirely)

When should I use Gregorian formatting?

Use Gregorian with Kurdish names for:

Use Kurdish calendar for:

Month and Day Names

Are the month and day names correct for my region?

The library uses documented sources:

Regional variations in dialect may exist due, the library represents the most standardised forms.

Why are some names different from what I know?

Kurdish has regional variations. The library aims to use widely accepted forms based on authoritative sources. If a dialect is missing, please contribute with authoritive sources and references.

Can I add my local dialect variation?

Yes! See the Contributing Guide for how to propose new dialects. We need:

We are particularly keen to add:

Technical Questions

Is the library thread-safe?

Yes. Date types are immutable value types (structs), making them inherently thread-safe. The internal equinox cache uses thread-safe operations.

Can I use this in ASP.NET Core / Blazor / MAUI?

Yes. The library is a .NET Standard/Core library with no dependencies, so it works in any .NET application:

Does it work on mobile devices?

Yes. Tested on:

What are the dependencies?

Zero external dependencies. The library only uses:

This makes it lightweight and easy to integrate.

Can I use this with Entity Framework?

Yes, but store as Gregorian DateTime in the database:

public class Event
{
  public int Id { get; set; }
  
  // Store as DateTime in database
  public DateTime EventDateGregorian { get; set; }
  
  // Not mapped - computed from EventDateGregorian
  [NotMapped]
  public KurdishDate EventDateKurdish 
  { 
    get => KurdishDate.FromDateTime(EventDateGregorian);
    set => EventDateGregorian = value.ToDateTime();
  }
}

Troubleshooting

“ArgumentOutOfRangeException: Month must be between 1 and 12”

You’re trying to create an invalid date:

// Wrong - Month 13 doesn't exist
var date = new KurdishDate(2725, 13, 1);

// Correct
var date = new KurdishDate(2725, 12, 1);

“FormatException: Unable to parse”

Parsing failed. Check:

  1. Input format matches supported patterns
  2. Dialect matches input language
  3. Month names are spelled correctly
// Use TryParse to handle errors gracefully
if (!KurdishDate.TryParse(input, dialect, out KurdishDate date))
{
  Console.WriteLine("Invalid format. Expected: dd/MM/yyyy or dd MonthName yyyy");
}

Date is one day off

Check if you’re mixing simplified and astronomical dates:

// These might differ by a day
KurdishDate simplified = new KurdishDate(2725, 1, 1);
KurdishAstronomicalDate astro = KurdishAstronomicalDate.FromErbil(2725, 1, 1);

Console.WriteLine(simplified.ToDateTime());  // 2025-03-21
Console.WriteLine(astro.ToDateTime());       // 2025-03-20 (actual equinox)

Arabic script or numerals not displaying correctly

Ensure you’re using:

  1. UTF-8 encoding in your files
  2. UTF-8 output (some terminals do not support RTL)
  3. Font that supports Eastern Arabic-Indic numerals
  4. Correct dialect (e.g., SoraniArabic not SoraniLatin)

Getting Help

Where can I find more examples?

How do I report a bug?

See Contributing Guide for bug reporting guidelines.

How do I request a feature?

Open a GitHub Issue with:

Still have questions?

بەختێکی باش! (Good luck!)