Coptic Date Converter

The Coptic date converter translates between the Gregorian calendar and the Coptic calendar used by the Coptic Orthodox Church and still followed for agricultural seasons in Egypt. Pick a Gregorian date to see the matching Coptic year, month, and day with month names, or enter a Coptic date as year-month-day to convert back.

How the Coptic calendar is built

The structure is unusually regular: twelve months of exactly thirty days each, followed by a short thirteenth month of five days, or six in the year preceding a leap year. Twelve thirties plus five gives 365 days, and the extra day every fourth year keeps the calendar aligned with the solar year the same way the Julian calendar does.

That regularity is a direct descendant of the ancient Egyptian civil calendar, reformed under Roman rule to add the leap day. Because every ordinary month has the same length, calculating a day number within a year is simple arithmetic rather than a lookup table — one reason the calendar remained practical for agricultural planning for so long.

The Era of the Martyrs

Coptic years are counted from the accession of the Roman emperor Diocletian, whose reign brought severe persecution of Egyptian Christians. Year one of the era corresponds to 284 in the common era, and Coptic years are written with the abbreviation AM, for Anno Martyrum — the year of the martyrs. Subtracting roughly 284 from a Gregorian year gives the Coptic year, though the exact offset depends on where in the year you are, because the Coptic new year does not fall on January 1.

Nayrouz and the new year

The Coptic year begins on 1 Thout, the feast of Nayrouz, which currently falls on September 11 in the Gregorian calendar, or September 12 in the year before a Coptic leap year. That date drifts slowly forward because the Coptic calendar uses the Julian leap rule of one leap day every four years, without the century exceptions the Gregorian reform introduced. The gap grows by roughly three days every four hundred years, which is why the correspondence that holds today did not hold centuries ago and will not hold indefinitely.

This drift is the main reason a converter is more reliable than a remembered rule. A fixed mapping of Coptic months to Gregorian dates is accurate only for the era in which it was written down.

Month names

The twelve regular months are Thout, Paopi, Hathor, Koiak, Tobi, Meshir, Paremhat, Parmouti, Pashons, Paoni, Epip, and Mesori, followed by the short month often called Pi Kogi Enavot or the epagomenal days. Transliterations vary considerably between sources, since the names pass through Coptic, Arabic, and Greek forms on their way into English. This converter uses one common set of spellings and also reports the numeric year-month-day form, which is unambiguous regardless of which transliteration your source prefers.

Feast days and the liturgical year

Coptic Christmas falls on 29 Koiak, which in the current era corresponds to January 7 in the Gregorian calendar. Fixed feasts like this keep a constant Coptic date while their Gregorian equivalent drifts with the same slow shift that moves Nayrouz. Moveable feasts, above all Easter, are calculated separately using a Julian-based Paschal computation rather than by direct date conversion — for that, see the Orthodox Easter calculator, which handles the rule the Coptic Church shares with other Eastern churches.

Agricultural use in Egypt

Beyond church use, the calendar survives in Egyptian farming, where the regular thirty-day months map cleanly onto planting and harvest seasons tied to the Nile's historic flood cycle. Almanacs and proverbs about weather and crops are still framed in Coptic months, and Egyptian farmers who never attend a Coptic liturgy may nonetheless plan the year by this calendar. That practical role is why the system remains in living use rather than existing only in liturgical books.

Reading Coptic dates in documents

Church records, family registries, and manuscripts from Egypt often give a Coptic date with no Gregorian equivalent. A date written with a month name and a year in the seventeen hundreds is Coptic, not a European date from the eighteenth century, and reading it as the latter shifts the record by roughly fifteen centuries. When a document gives both calendars, use the pair to confirm your conversion method before trusting it on entries that give only one.

Some sources abbreviate the era marker or omit it entirely, relying on context that a modern reader may not share. If a year number sits between about 1500 and 1800 in a document that also mentions recent events, the Coptic reading is almost certainly the intended one.

Notes on accuracy

This converter uses the standard arithmetic mapping between the Coptic calendar and the Julian day count, which is exact for the calendar as defined. For dates in the distant past, remember that applying any calendar backwards beyond its historical adoption produces a proleptic result: mathematically consistent but not something anyone at the time would have written. Label such results clearly in scholarly work.

Also keep in mind that liturgical days traditionally begin at sunset rather than midnight. A converter works in civil days, so an evening event may carry the following Coptic date in a church context.

Related calendars

The Ethiopian calendar shares the identical thirteen-month structure and leap rule, differing only in its epoch and month names, so the two run in perfect step with a fixed year offset. For the historical European calendar that shares the Coptic leap rule, see Julian to Gregorian. Other systems are covered by the Hebrew, Islamic, and Persian converters, and everything is listed on the converters hub.

Checking a conversion

Convert in both directions and confirm you return to the date you started with. If a result seems a month off, check whether your source counted the epagomenal days as part of Mesori rather than as a separate thirteenth month — that difference in convention shifts the final week of the year. If it seems a year off, check whether the date falls between September 11 and December 31, where the Coptic year has already advanced while the Gregorian year has not.