AthanLib is a lightweight and dependency-free C++ library for calculating Islamic prayer times based on astronomical formulas.
It provides accurate timings for Fajr, Dhuhr, Asr, Maghrib, and Isha anywhere in the world.

• 📅 Compute daily prayer times for any date and location
• 🧭 Handles latitude, longitude, and timezone offsets
• ⚙️ Simple API, easy to integrate into any C++ project
• 🪶 Lightweight, no external libraries or dependencies
• 🧮 Based on well known astronomical conventions used around the world and in many countries

You don’t need to install anything special, just clone it and place the files in whatever project you're using it for.

git clone https://github.com/earthtojad/AthanLib.git
cd AthanLib

Copy these two files into your project:

AthanLib.cpp
AthanLib.h

Then include it in your code:

#include "AthanLib.h"

That’s it! 🎉

Here’s a simple example:

#include <iostream>
#include "AthanLib.h"

int main() {
    // Create a PrayerTimes object
    PrayerTimes today;

    // Example inputs: 06-Oct-2025, Los Angeles, California, United States of America.    
    int day = 6;
    int month = 10;
    int year = 2025;


    const double timeZone = -7.0;
    const double lat = 34.0549; //REMINDER: if latitude is south or longitude is west, please make sure that the value is set to negative.
    const double lon = -118.2426;



    // Calculate prayer times
    today.calcPrayerTimes(day, month, year, lat, lon, timeZone, ISNA);

    // Display results
    std::cout << "Date: " << day << "/" << month << "/" << year << std::endl;
    std::cout << "Location: " << lat << ", " << lon << " (UTC" << timeZone << ")" << std::endl;
    std::cout << "----------------------------------------" << std::endl;
    std::cout << "Fajr:     " << getTime(today.fajr) << std::endl;
    std::cout << "Sunrise:  " << getTime(today.sunrise) << std::endl;
    std::cout << "Dhuhr:    " << getTime(today.dhuhr) << std::endl;
    std::cout << "Asr (Shafi'i):  " << getTime(today.asr1) << std::endl;
    std::cout << "Asr (Hanafi):   " << getTime(today.asr2) << std::endl;
    std::cout << "Maghrib:  " << getTime(today.maghrib) << std::endl;
    std::cout << "Isha:     " << getTime(today.isha) << std::endl;
    std::cout << "----------------------------------------" << std::endl;

    return 0;
}

Output:

Date: 6/10/2025
Location: 34.0549, -118.243 (UTC-7)
----------------------------------------
Fajr:     05:43
Sunrise:  06:51
Dhuhr:    12:41
Asr (Shafi'i):  16:00
Asr (Hanafi):   16:49
Maghrib:  18:31
Isha:     19:39
----------------------------------------

You can choose a prayer time convention by setting the angle parameters directly in code.

Below is a reference of common conventions with suggested variable names and their corresponding Fajr and Isha angles:

Angles are negative because they are below the horizon.

Just replace the ConvectionAngle parameter with whatever calculation method you follow:

PrayerTimes today;
today.calcPrayerTimes()
today.calcPrayerTimes(day, month, year, lat, lon, timeZone, MWL); //Keep in mind in the example code we used ISNA as we're in North America

AthanLib/
 ├── AthanLib.cpp      # Core calculation code
 ├── AthanLib.h        # Header file
 ├── example.cpp       # Example usage
 └── LICENSE           # GPL-3.0 license

AthanLib is released under the GPL-3.0 License.
You are free to use, modify, and redistribute it, provided that your project also uses the GPL-3.0 license.

Contributions are welcome!
If you find bugs, want to add regional calculation methods, or improve documentation:

1. Fork the repo
2. Create a new branch:

   git checkout -b feature/my-improvement

3. Commit your changes and open a Pull Request

-Prayer Times Calculation, https://praytimes.org/docs/calculation

-Computing Approximate Solar Coordinates, https://aa.usno.navy.mil/faq/sun_approx

-Twilight formula correction sources: https://astronomycenter.net/pdf/mohamoud_2017.pdf & https://www.sjctni.edu/Department/ma/eLecture/Twilight.pdf

-Sign function: https://en.wikipedia.org/wiki/Sign_function

Developed by earthtojad
Inspired by traditional Islamic prayer time algorithms and open-source astronomical research.

“Indeed, prayer has been decreed upon the believers a decree of specified times.” — Qur’an 4:103