Persian Calendar Converter

How to Use the Persian Calendar Converter

1. 1. Choose the direction. Gregorian → Persian opens on today's date. For Persian → Gregorian, enter the day, pick the month and type the year (SH, Solar Hijri).
2. 2. Read the result. You get the Persian date, the same date in Persian script with Persian digits, the Gregorian date, the weekday and the ISO date. Dates before October 1582 also show the Julian date.
3. 3. Check the year. Under the result are the month's length, whether the year is a leap year, and the March equinox — its exact minute in Tehran time and in UTC — that fixed Nowruz.
4. 4. Compare the methods. The converter also says whether the common 33-year arithmetic rule gives the same date. For the present century the two always agree.

How the Persian Calendar Works

The Solar Hijri calendar is a solar calendar: its year is a tropical year, and it begins on Nowruz, the day of the March equinox. The first six months have 31 days, the next five have 30, and Esfand has 29 days — or 30 in a leap year. A common year therefore has 365 days and a leap year 366. Years are counted from the Hijra, the year of Muhammad's migration to Medina in 622 CE, but unlike the Islamic lunar calendar they follow the sun, so year numbers stay close to the Gregorian year minus 621 or 622.

The year number changes at Nowruz, not on 1 January. A date on or after Nowruz is the Gregorian year minus 621; a date before it, the Gregorian year minus 622. So January 2000 falls in 1378 and April 2000 in 1379.

Astronomical, Not Arithmetic

Iran's official calendar is defined by observation. The year starts on the day the March equinox occurs before noon on the Iran Standard Time meridian (52.5° E, UTC+3:30); if the equinox falls after noon, the year starts the next day. The equinox of 2025 came at 12:31 Tehran time, half an hour after noon, so 1 Farvardin 1404 was Friday 21 March 2025. The equinox of 2024 came at 06:36, so 1 Farvardin 1403 was Wednesday 20 March 2024.

This converter computes that equinox with the formulas in Jean Meeus, Astronomical Algorithms (2nd ed., 1998), corrected for the Earth's uneven rotation, and builds the calendar on it as set out in Reingold and Dershowitz, Calendrical Calculations: The Ultimate Edition (Cambridge University Press, 2018). It reproduces the equinox instants published for 2000 and for 2020–2026 to within a minute, and agrees with the date library built into browsers on every day from 1921 to 2071.

Many programs use a shortcut instead: a 33-year cycle in which year y is a leap year when (25y + 11) mod 33 is less than 8. It needs no astronomy, and from 1178 to 1634 SH (1799–2255 CE) it gives the same Nowruz as the equinox rule. The first year in which the two differ is 1635 SH (2256 CE). Dates earlier than the 1925 law that made the calendar official are calculated backwards.

Worked Examples

• 1 January 2000 is Saturday 11 Dey 1378, in a year that began on 21 March 1999.
• 11 February 1979, the day the monarchy fell, is Sunday 22 Bahman 1357 — the date Iran marks every year as the Revolution anniversary.
• 20 March 2025 is 30 Esfand 1403, the last day of a leap year, and 21 March 2025 is Friday 1 Farvardin 1404. The year 1405 began on Saturday 21 March 2026.

Accuracy and Limits

The equinox is accurate to a few minutes, which settles the Nowruz day in nearly every year. The exception is a year in which the equinox lands close to noon in Tehran; then a minute's error can move the whole year by a day. For the future the result also depends on the Earth's rotation, which cannot be predicted far ahead, so read dates a century or more away as predictions. For a date that matters legally, check the official calendar Iran publishes for that year.

Frequently Asked Questions

What is the difference between the Persian, Jalali, Shamsi and Solar Hijri calendars?

They are the same calendar under different names. Persian and Jalali (after Jalal al-Din Malik-Shah, whose astronomers devised it in the 11th century) are the common English names. Shamsi, Arabic for solar, is the usual name in Afghanistan and South Asia, and Solar Hijri is the formal one. Iran's version has been official since 1925.

How do I convert a Gregorian date to a Persian date?

Pick the Gregorian date in Gregorian → Persian. The tool finds the Nowruz that began that Persian year, counts the days since it, and splits them into months of 31, 30 and 29 or 30 days. The year number is the Gregorian year minus 621 on or after Nowruz and minus 622 before it.

When is Nowruz, and why does its date change?

Nowruz is the first day of Farvardin, the day of the March equinox as seen from Tehran. Between 1800 and 2100 it falls on 20, 21 or 22 March, and on 21 March in about two years out of three. The date moves because the equinox itself falls at a different hour each year, and Iran starts the year that day only if the equinox is before noon.

How do I tell whether a Persian year is a leap year?

A year is a leap year when 1 Farvardin of the next year is 366 days after its own. Recent leap years are 1399, 1403 and 1408. In the 33-year approximation the test is that (25 × year + 11) mod 33 is less than 8, which gives the same answers for the current century.

Why do the Persian months have 31 days at the start of the year?

The sun moves more slowly along the ecliptic in spring and summer, so those seasons last longer. The calendar gives 31 days to the first six months, 30 to the next five, and the remainder to Esfand. Six months of 31 days and five of 30 make 336 days, and the 29 days of Esfand bring the total to 365.

Is the Persian calendar the same as the Afghan one?

Closely related. Afghanistan uses the same Solar Hijri year numbers and month lengths, but its months have different names — Hamal, Saur, Jawza and so on, after the zodiac signs. Its day boundaries are not defined by the Tehran noon rule, so check an Afghan source for a date that matters. This converter applies the Iranian rule and the Persian month names.