How to convert a birth date between the Shamsi and Miladi calendars

Converting a birth date between the Persian Solar Hijri (Shamsi or Jalali) calendar and the Gregorian (Miladi) calendar is one of the most common reasons people reach for a date converter. You might need it for a passport or visa application, a school or university record, an immigration form, or simply to know which day to celebrate a birthday abroad. This guide walks through the process and shows a complete worked example.

Why birth dates need careful conversion

Iranian official documents use the Shamsi calendar, while most countries outside Iran use the Gregorian (Miladi) calendar. A birth date written as 15 Mordad 1370 means nothing to a Gregorian-only system, and a date like 6 August 1991 means nothing on an Iranian form. Because the two calendars start their years at different points and follow different leap-year rules, you cannot simply add or subtract a fixed number of years. Each date has to be converted exactly, day by day.

A worked example

Suppose a birth date is recorded as 15 Mordad 1370 on a Persian document and you need the Gregorian equivalent.

1. Open the converter.
2. Enter the Shamsi date: year 1370, month Mordad (the fifth month), day 15.
3. Read the Gregorian result: 6 August 1991.

The conversion works in both directions. If you start from 6 August 1991 and convert the other way, you get back 15 Mordad 1370 — the result round-trips exactly, which is a good way to double-check any conversion. To go from Gregorian to Persian see Gregorian to Shamsi, and for the reverse see Shamsi to Gregorian.

Day-only accuracy: no time zones involved

A birth date is a calendar day, not a moment in time. This converter uses a date-only model with no hours, minutes, or time zones, so the result never shifts because of where you happen to be. A date entered in Tehran and the same date entered in London produce the identical answer. That matters for documents, where an off-by-one-day error from a time-zone rollover can cause real problems.

Watch the months and the calendar boundary

The Persian months are Farvardin, Ordibehesht, Khordad, Tir, Mordad and Shahrivar (each 31 days), then Mehr, Aban, Azar, Dey and Bahman (each 30 days), and finally Esfand (29 days, or 30 in a leap year). The Persian year begins on Nowruz, 1 Farvardin, which falls on about 20–21 March. Because of this, a single Persian year spans parts of two Gregorian years. A birthday early in Farvardin lands in late March; one in late Esfand lands the following March. If a result looks like it is in the "wrong" Gregorian year, this boundary is usually the reason — see Persian months and leap years for the details.

Verifying against official documents

When the conversion is for a passport, visa, birth certificate or other official record, take a moment to confirm a few things:

• Read the source date carefully. Make sure you have the right month name and that the day and month have not been swapped.
• Convert both ways. Convert your result back to the original calendar and check it matches the document.
• Match the document's own format. Some documents already print both calendars — if so, your conversion should agree with what is printed.

For accuracy, this converter cross-checks every result against the browser's built-in Persian calendar, and a date is only accepted when both calendars agree and the counterpart year is within the supported range (Jalali years 1–1700 and Gregorian years 622–2322). Common slip-ups are covered in common mistakes.

Working out an age

If you also need to know someone's age — for a form that asks for years and months, for example — use the age calculator. It works from a birth date in either calendar and gives an exact age, so you do not have to do the arithmetic across the calendar boundary by hand.

Privacy

The conversion runs entirely in your browser. No birth date is sent to a server, and the converter itself sets no cookies and makes no network calls to convert a date. (Optional advertising or analytics, if the site owner enables them and you consent, are separate layers and off by default.) You can read more on the privacy page, and the app keeps working offline once it has loaded.