Shamsi, Jalali, Persian — one calendar, three names
The Shamsi calendar is the official calendar of Afghanistan and Iran. Shamsi means solar; you will also see it called Jalali, after the reform of 1079 that fixed its present shape, or simply the Persian calendar, which is what most software calls it. Miladi is the Gregorian calendar — the ordinary international one.
It is a solar calendar, so its year is the same length as a Gregorian year and the seasons stay where they belong. That is worth stating because it is the single most common confusion here: the Shamsi calendar is not the Islamic Hijri calendar, which is lunar, eleven days shorter, and drifts steadily through the seasons. The two are currently about forty years apart in their year numbers.
The months, and their two sets of names
There are twelve months. The first six have 31 days, the next five have 30, and the twelfth — Esfand, or Hut — has 29 days, or 30 in a leap year. Afghanistan names them with the zodiacal Arabic terms and Iran with the Persian ones, but they are the same months in the same order, so a date written either way is the same day:
| # | Afghan name | Iranian name | Days |
|---|---|---|---|
| 1 | Hamal | Farvardin | 31 |
| 2 | Sawr | Ordibehesht | 31 |
| 3 | Jawza | Khordad | 31 |
| 4 | Saratan | Tir | 31 |
| 5 | Asad | Mordad | 31 |
| 6 | Sunbula | Shahrivar | 31 |
| 7 | Mizan | Mehr | 30 |
| 8 | Aqrab | Aban | 30 |
| 9 | Qaws | Azar | 30 |
| 10 | Jadi | Dey | 30 |
| 11 | Dalw | Bahman | 30 |
| 12 | Hut | Esfand | 29 or 30 |
Worked examples
20 March 2024 converts to 1 Farvardin 1403 (1 Hamal in the Afghan names) — Nowruz that year. The day before, 19 March 2024, is 29 Esfand 1402, the last day of the old year, which shows 1402 was a common year: Esfand only reaches 29 days, not 30. Going the other way, 25 Ordibehesht 1369 (25 Sawr in the Afghan names) converts to 15 May 1990.
Why the new year moves
Nowruz, the Shamsi new year, is the day of the March equinox as observed at Tehran. It is an astronomical event rather than a fixed count, so 1 Hamal falls on 20 or 21 March depending on the year — and because of that, the leap years do not follow a neat repeating pattern the way the Gregorian ones do. Any converter that uses a simple thirty-three-year cycle will eventually give you the wrong day.
The rule of thumb people usually reach for — add 621 to a Shamsi year — gets you the Gregorian year that mostly overlaps it. Shamsi 1402 ran from 21 March 2023 to 19 March 2024. But since every Shamsi year straddles two Gregorian ones, that addition tells you which year, not which day. For a date you can put on a form, use the converter.
Where the conversion comes from
This page does no calendar arithmetic of its own. Every conversion is performed by the internationalisation library built into your browser, which is maintained by the Unicode Consortium and is the same code your operating system uses to display dates. Writing that arithmetic by hand would mean reproducing a long table of leap-year exceptions from memory, and getting one entry wrong would produce answers that look right and are not.
The one thing the page does calculate is the reverse direction, which the browser does not offer directly. It searches for the day whose forward conversion matches what you typed, and confirms the match exactly rather than settling for close. If no day converts to the date you entered — 30 Hut in a common year, for instance — it tells you the date does not exist instead of silently moving you.
Common mistakes
- Adding 621 and treating it as an exact conversion. It only tells you which Gregorian year a Shamsi year mostly falls in. The actual day needs the converter, because the Shamsi year starts in March and runs into the following Gregorian year.
- Assuming Esfand always has 30 days. It does only in a leap year. In a common year, like 1402, it stops at 29, and "30 Esfand 1402" is not a date the converter can return.
- Confusing Shamsi with Hijri. Both count from the Hijra and both are sometimes just called "the Hijri calendar" in casual speech, but Shamsi is solar and Hijri is lunar — use the Hijri date converter if the date in front of you is a Ramadan or an Eid date rather than an Iranian or Afghan calendar date.
Limits
Conversions are for whole days, not times, so time zones do not come into it: a date is a date. "Today" is taken from your device's clock and your device's time zone, which means someone in Kabul and someone in Toronto can genuinely see different days for a few hours, exactly as they would on a wall calendar.
Very old dates are converted the way the standard implementation converts them, by extending the modern rules backwards. That is the normal convention, but it is a convention: for historical research before the calendar's adoption, a proleptic conversion is not the same thing as what a document of the period would have said.
Related tools
For the lunar Islamic calendar — a different calendar despite the shared Hijra starting point — see the Hijri date converter or the Hijri age calculator.