Persian (Shamsi) date converter: Shamsi to Gregorian and Gregorian to Shamsi

How the Solar Hijri calendar works

The Solar Hijri calendar, also called Shamsi or Jalali, is the official calendar of Iran, defined by a law of 1925 (1304 in its own count), and it is also used in Afghanistan. It is a solar calendar: the year follows the seasons exactly and always begins at the March equinox.

The first six months have 31 days and the next five have 30. Esfand, the last month, has 29 days in a common year and 30 in a leap year. That gives 365 or 366 days, with the long months in spring and summer.

Each year begins on Nowruz, 1 Farvardin. Nowruz is the day of the March equinox if the equinox comes before noon in Tehran, and the next day if it comes after noon. The calendar is computed and published each year by the Calendar Center of the University of Tehran’s Institute of Geophysics.

Nowruz dates

Noon in Tehran is about 08:30 to 08:45 UT. In 2026 the equinox came at 14:46 UT, well after Tehran noon, so Nowruz 1405 was on 21 March. In 2029 it comes at 08:02 UT, just before noon, so Nowruz 1408 is on the day of the equinox itself, 20 March.

The converter shows the Nowruz of the year for every date you enter.

Converting by hand

Count the days from Nowruz. 23 October 2026 is 216 days after 21 March 2026. The first six months use 186 of those days (6 × 31), and Mehr uses 30 more. The remaining day falls on the first of the next month, Aban, so the date is 1 Aban 1405. The day-of-year converter gives the Gregorian side of the count: 23 October is day 296 of 2026 and 21 March is day 80.

For the year alone, add 621 to the Shamsi year for dates from Nowruz to 31 December and 622 for dates from January to the end of Esfand. So 1405 runs from 21 March 2026 to 20 March 2027.

Leap years and the 33-year rule

Because the calendar is astronomical, a year is a leap year when the next Nowruz comes 366 days after its own, which adds a 30th day to Esfand. In practice the pattern follows a 33-year cycle: a year is a leap year when its remainder after dividing by 33 is 1, 5, 9, 13, 17, 22, 26 or 30. Leap years from 1395 to 1420 are 1395, 1399, 1403, 1408, 1412, 1416 and 1420.

The converter uses that rule. We compared it with the astronomical calendar, and it gives the same Nowruz in every year from 1178 to 1501 AP (1799 to 2123). After that the equinox falls close to Tehran noon and sources disagree, so later results are predictions.

Some older converters use a 2820-year cycle instead. It does not match the astronomical calendar in modern times. It treats 1404 as a leap year instead of 1403, so it puts Nowruz 1404 on 20 March 2025 instead of the correct 21 March.

Month names in Iran and Afghanistan

Iran uses the Persian month names Farvardin to Esfand. In Afghanistan the same months are named after the signs of the zodiac, starting with Hamal (Aries) and ending with Hut (Pisces). The years and month lengths are the same, so 1 Aban 1405 in Iran is 1 Aqrab 1405 in Afghanistan. The table beside the converter gives both names with the usual start date of each month.

Solar Hijri and lunar Hijri are different calendars

Both calendars count years from the Hijra of 622 CE, which causes confusion. The Islamic (lunar) Hijri calendar has years of 354 or 355 days, so it has gained years on the solar one. On 23 October 2026 the Solar Hijri date is 1 Aban 1405 and the lunar date is 12 Jumada al-Ula 1448 AH.

For the lunar calendar, use the Hijri date converter. The How we calculate page lists the tests behind both converters.

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