How to use the persian calendar converter
- Choose Gregorian to Persian or Persian to Gregorian.
- For Gregorian to Persian, pick the Gregorian date from 1800 to 2100.
- For Persian to Gregorian, enter the Persian year (1178 to 1479), pick the month and enter the day.
- Read the converted date, the weekday, the day of the Persian year and the leap year status.
Formula
Persian leap year: (25 x year + 11) mod 33 < 8
months 1 to 6 have 31 days, months 7 to 11 have 30, Esfand has 29 or 30
days from the epoch = 365 x (year - 1) + floor((8 x year + 21) / 33) + days before the month + day
Both calendars are turned into a Julian day number, a plain count of days, so any date can be converted to the other calendar and back.
Nowruz, the Persian new year
March 21, 2026 is Saturday, 1 Farvardin 1405, the first day of the Persian year. March 21, 2021 was Sunday, 1 Farvardin 1400. Going the other way, 1 Mehr 1405, the first day of the seventh month, is Wednesday, September 23, 2026, which is the 187th day of the Persian year.
The year 1403 is a leap year, so its last month has 30 days. March 20, 2025 is Thursday, 30 Esfand 1403, the 366th day of that year, and 1 Farvardin 1404 follows on March 21, 2025.
How the Persian calendar works
The Persian or Solar Hijri calendar is a solar calendar whose year begins at the spring equinox, on the day called Nowruz. The first six months have 31 days, the next five have 30, and the last month, Esfand, has 29 days, or 30 in a leap year. Year numbers count from 622 CE, so the Persian year is about 621 or 622 years behind the Gregorian one.
The calendar used in Iran is set by observing the equinox. Over recent centuries, a repeating 33 year cycle with 8 leap years matches it closely, and this page uses that rule. In a few years the observed calendar may differ from the rule by one day, so check an important date against a published calendar.
Related calendars
For the Islamic lunar calendar, use the Hijri Date Converter. For the Hebrew calendar, use the Hebrew Date Converter. The Julian to Gregorian Date Converter covers the older calendar from which the Gregorian calendar grew, and the Day of the Week Calculator gives the weekday of any date.
Assumptions and limits
- The calendar follows the 33 year arithmetic rule, not the observed equinox.
- The converter covers Gregorian dates from 1800 to 2100 (Persian years 1178 to 1479).
- A date is a calendar day. Time of day and time zones are not considered.
- Month names use common Latin spellings, which vary between sources.
- The dates shown when the page opens are examples.
Frequently asked questions
Why does the range stop at 1800 and 2100?
The arithmetic rule fits the calendar as it has been used in recent centuries. Outside that range it is less reliable, and the page would be guessing.
What is Nowruz?
It is the first day of the Persian year, 1 Farvardin, which falls on the day of the spring equinox in Tehran or the day after, usually March 20 or 21.
How can a year have 366 days?
In a leap year Esfand has 30 days instead of 29. The year then has 366 days. Leap years follow the 33 year cycle: 1399, 1403, 1408 and 1412 are leap years.
Is the Persian calendar the same as the Islamic calendar?
No. The Persian calendar is solar, with years of about 365.24 days. The Islamic calendar is lunar, with years of about 354 days, so its dates move through the seasons.