Select Date & Calendar

Source Calendar Gregorian
Select the calendar system of your input date
Source Date January 15, 2025
Enter the date you want to convert
Quick Select Today
Quickly select common dates
Target Calendar Hijri
Select the calendar to convert to
Date Format DD/MM/YYYY
Select the display format for converted date
15/01/2025
Gregorian
Monday
04/07/1445
Hijri (Islamic)
Monday

Date Information

15th
Day of Year
3
Week Number
31
Days in Month
Capricorn
Zodiac Sign

Date in Different Formats

ISO 8601
2025-01-15
Long Date
January 15, 2025
RFC 2822
Mon, 15 Jan 2025
Unix Timestamp
1705286400

Calendar Comparison

Calendar Date Year Type Days in Year

Related Dates

This date is 5 days after New Year's Day and 20 days before February 4 (World Cancer Day).

About Calendar Systems

Gregorian Calendar

The solar calendar used internationally for civil purposes. Introduced in 1582 by Pope Gregory XIII.

Year Length: 365.2425 days
Leap Year: Every 4 years (except century years not divisible by 400)
Used In: Worldwide for civil purposes
Start Year: 1 AD (Anno Domini)

Hijri Calendar

The Islamic lunar calendar used for religious purposes. Begins with Hijra (migration) of Prophet Muhammad.

Year Length: 354-355 days
Leap Year: 11 leap years in 30-year cycle
Used In: Islamic religious events
Start Year: 622 AD (Year of Hijra)

Julian Calendar

The solar calendar introduced by Julius Caesar in 46 BC. Used before Gregorian reform.

Year Length: 365.25 days
Leap Year: Every 4 years without exception
Used In: Historical dates, Orthodox churches
Start Year: 45 BC

Hebrew Calendar

The lunisolar calendar used for Jewish religious observances. Based on lunar months with solar corrections.

Year Length: 353-355 or 383-385 days
Leap Year: 7 times in 19-year cycle
Used In: Jewish religious events
Start Year: 3761 BC (Creation)

About Date Converter

The Date Converter allows you to convert dates between different calendar systems including Gregorian, Hijri (Islamic), Julian, and Hebrew calendars. It also calculates date differences and provides various date formats for your convenience.

How Date Conversion Works

1

Convert to Julian Day Number

Each calendar date is first converted to a Julian Day Number (JDN) - a continuous count of days from January 1, 4713 BC.

2

Apply Calendar Algorithms

Specific algorithms for each calendar system are applied to convert the JDN to the target calendar's date format.

3

Calculate Date Differences

Date differences are calculated by subtracting Julian Day Numbers and converting back to days, weeks, and months.

4

Format Display

The converted date is formatted according to selected display preferences and international standards.

Common Date Conversions

Gregorian Date Hijri Date Julian Date Hebrew Date
January 1, 2025 19 Jumada al-thani 1445 December 19, 2023 20 Tevet 5784
March 21, 2025 11 Ramadan 1445 March 8, 2025 11 Adar II 5784
July 4, 2025 28 Dhu al-Hijjah 1445 June 21, 2025 28 Tammuz 5784
December 25, 2025 24 Jumada al-awwal 1446 December 12, 2025 24 Kislev 5785

Date Format Standards

ISO 8601

International standard: YYYY-MM-DD (e.g., 2025-01-15). Used worldwide for data exchange.

US Format

MM/DD/YYYY (e.g., 01/15/2025). Used in United States, Philippines, and some Caribbean nations.

European Format

DD/MM/YYYY (e.g., 15/01/2025). Used in most of Europe, Asia, Africa, and Oceania.

Long Format

Month Day, Year (e.g., January 15, 2025). Used in formal documents and publications.

Tips for Date Conversion

Historical Dates

For dates before 1582, use Julian calendar as Gregorian wasn't introduced yet.

Hijri Accuracy

Hijri dates may vary by 1-2 days based on moon sighting in different regions.

Time Zone Awareness

Date conversion may be affected by time zones for dates around midnight.

Leap Years

Different calendars have different leap year rules affecting conversion accuracy.

Note: Date conversions are based on standard algorithms and may have slight variations from local astronomical observations. Hijri dates are calculated using the Umm al-Qura calendar for Saudi Arabia. Hebrew calendar calculations follow the modern rules established by Hillel II. Historical date conversions for periods before calendar reforms may have regional variations.

How accurate is the date converter?

Our date converter uses established astronomical algorithms and is accurate for most practical purposes. However, for religious observances, local moon sightings may cause 1-2 day variations for Hijri dates.

What is the difference between Gregorian and Julian calendars?

The Julian calendar has a leap year every 4 years without exception (365.25 days/year). The Gregorian calendar skips leap years in century years not divisible by 400 (365.2425 days/year), making it more astronomically accurate.

How do I convert Hijri dates to Gregorian?

Select "Hijri" as source calendar, enter the Hijri date, select "Gregorian" as target calendar, and click convert. The calculator uses the Umm al-Qura system for conversion.

What is a Julian Day Number?

Julian Day Number is a continuous count of days since noon Universal Time on January 1, 4713 BC. It's used in astronomy and calendar conversion calculations.

Why are there different date formats?

Different countries and cultures use different date formats. ISO 8601 (YYYY-MM-DD) is the international standard, while MM/DD/YYYY is common in the US and DD/MM/YYYY in most other countries.