🎯 Professional Calendar Converter
🌍 Gregorian Calendar
The most widely used civil calendar system worldwide, introduced by Pope Gregory XIII in 1582.
- Solar calendar with 365/366 days
- Leap year every 4 years (with exceptions)
- Used internationally for civil purposes
- Year 2025 CE (Common Era)
🏛️ Julian Calendar
Roman calendar system introduced by Julius Caesar, predecessor to the Gregorian calendar.
- Solar calendar with 365.25 days average
- Simple leap year every 4 years
- Still used by some Orthodox churches
- 13-day difference from Gregorian
🕌 Hijri Calendar
Islamic lunar calendar starting from the Hijra (migration of Prophet Muhammad to Medina).
- Lunar calendar with 354/355 days
- 12 months based on moon phases
- Year 1447 AH (Anno Hegirae)
- Used for Islamic religious observances
✡️ Hebrew Calendar
Jewish lunisolar calendar used for religious observances and the civil calendar in Israel.
- Lunisolar calendar with 353-385 days
- Leap months to align with solar year
- Year 5785 AM (Anno Mundi)
- Dates from creation of the world
🇮🇷 Persian Calendar
Solar calendar used in Iran and Afghanistan, highly accurate astronomical calendar.
- Solar calendar with 365/366 days
- Extremely accurate leap year system
- Year 1404 AP (Anno Persico)
- Based on spring equinox
🧘 Buddhist Calendar
Calendar system used in Buddhist countries, starting from the death of Buddha.
- Various regional implementations
- Year 2568 BE (Buddhist Era)
- Used in Thailand, Sri Lanka, Myanmar
- Based on lunar or solar systems
📊 Calendar Systems Overview
🌍 Gregorian Calendar Details
The international standard calendar system with sophisticated leap year calculations.
- Introduced: October 15, 1582
- Average year: 365.2425 days
- Leap rule: Divisible by 4, except centuries unless divisible by 400
- Error: 1 day in 3,030 years
- Adoption: Gradually worldwide from 1582-1923
🏛️ Julian Calendar Details
Simple and effective calendar system used for over 1,600 years.
- Introduced: 46 BCE by Julius Caesar
- Average year: 365.25 days
- Leap rule: Every 4 years without exception
- Error: 1 day in 128 years
- Still used: Some Orthodox churches
🕌 Hijri Calendar Details
Pure lunar calendar for Islamic religious observances and civil use.
- Started: July 16, 622 CE (Hijra)
- Year length: 354.367 days average
- Months: 12 lunar months (29-30 days)
- Leap years: 11 in every 30-year cycle
- Usage: Islamic religious dates, Saudi Arabia civil calendar
✡️ Hebrew Calendar Details
Complex lunisolar system balancing lunar months with solar year.
- Started: October 7, 3761 BCE (traditional)
- Year length: 353-385 days
- Leap months: 7 in every 19-year cycle
- Complexity: Four different year types
- Usage: Jewish religious calendar, Israel civil calendar
🇮🇷 Persian Calendar Details
Astronomically accurate solar calendar with sophisticated calculations.
- Started: March 22, 622 CE
- Year length: 365.2422 days
- Accuracy: Most accurate calendar system
- Leap rule: Complex astronomical algorithm
- Usage: Iran and Afghanistan official calendar
🧘 Buddhist Calendar Details
Various implementations across Buddhist countries with different systems.
- Started: 544 BCE (Buddha's death)
- Variations: Thai, Sri Lankan, Myanmar systems
- Base: Lunar or lunisolar depending on country
- Year length: Varies by implementation
- Usage: Religious observances in Buddhist countries
📜 Historical Calendar Events
🏛️ Calendar Reforms
Major historical changes in calendar systems throughout history.
- 46 BCE: Julius Caesar introduces Julian calendar
- 325 CE: Council of Nicaea standardizes Easter calculation
- 1582: Pope Gregory XIII introduces Gregorian calendar
- 1752: Britain adopts Gregorian calendar (11-day jump)
- 1918: Russia adopts Gregorian calendar (13-day jump)
🌍 Global Adoption
Timeline of Gregorian calendar adoption worldwide.
- 1582: Catholic countries (Italy, Spain, Portugal)
- 1700: Protestant German states
- 1752: British Empire (including American colonies)
- 1873: Japan adopts Gregorian calendar
- 1949: China officially adopts Gregorian calendar
📅 Calendar Accuracy
Comparison of calendar system accuracy and astronomical alignment.
- Julian: 1 day error in 128 years
- Gregorian: 1 day error in 3,030 years
- Persian: 1 day error in 141,000 years
- Hebrew: Self-correcting lunisolar system
- Hijri: Pure lunar, no solar alignment needed
🎯 Notable Dates
Important historical dates in different calendar systems.
- Hijra: July 16, 622 CE (Islamic calendar epoch)
- Hebrew creation: October 7, 3761 BCE (traditional)
- Persian New Year: March 21 (spring equinox)
- Buddha's death: 544 BCE (Buddhist calendar epoch)
- Gregorian reform: October 4→15, 1582 (10-day jump)