The Persian (Solar Hijri) Months

The Iranian calendar — known as Shamsi or Jalali, and formally the Solar Hijri calendar — divides the year into twelve months, just like the Gregorian (Miladi) calendar. The difference is in the names, the day counts, and where each month sits against the Gregorian year. This page lists all twelve months, how many days each one has, and the approximate Gregorian span each covers.

When the Persian year begins

The Persian year starts on Nowruz — 1 Farvardin — which falls on or around 20–21 March, at the spring equinox. Because the Persian new year lands near the end of March rather than on 1 January, every Persian month straddles two Gregorian months. For example, 1 Farvardin 1404 corresponds to 21 March 2025, and 1 Farvardin 1403 corresponded to 20 March 2024.

The twelve months at a glance

The first six months each have 31 days, the next five each have 30 days, and the final month, Esfand, has 29 days in an ordinary year and 30 in a leap year. The Gregorian spans below are approximate: because of leap years in both calendars, the exact start and end can shift by about a day from year to year.

Why the first half of the year is longer

Grouping the long months at the start of the year is not arbitrary. The Earth moves a little more slowly along its orbit during the northern spring and summer, so the sun spends slightly longer in the first six zodiacal signs. The Solar Hijri calendar reflects this astronomical reality by giving its first six months 31 days each. It is one of the reasons the calendar tracks the seasons so closely.

Esfand and leap years

The only month whose length changes is Esfand, the last month of the year. In an ordinary year it has 29 days; in a leap year it gains a 30th day, so that the year totals 366 days. A well-known example is 30 Esfand 1399, which fell on 20 March 2021 — that extra day existed only because 1399 was a leap year.

Persian leap years do not follow the simple Gregorian rule of "every fourth year". They are determined by a precise arithmetic cycle (the proven 33-year pattern used by this converter). If you would like to understand exactly how leap years are decided in each calendar, see our guide to leap years.

Converting any Persian date

Knowing the month spans is useful for a rough mental conversion, but for an exact date in either direction you can use the converter on the home page. It works entirely in your browser, with no server and no network call, so your dates stay private. You can also read the step-by-step guides for Shamsi to Gregorian and Gregorian to Shamsi, or check the frequently asked questions.