The phrase Old Calendar usually refers to the Julian calendar for fixed feasts. New Calendar usually refers to the Revised Julian calendar for fixed feasts. For the years 1900 through 2099, Julian calendar dates fall 13 days behind the civil Gregorian calendar.
Nativity is celebrated on December 25 by churches using the New Calendar for fixed feasts.
Julian December 25 currently appears as January 7 on the civil calendar.
Nativity, Theophany, Dormition, and many saints' days may appear on different civil dates.
Many Orthodox churches use a shared traditional Paschal calculation even when fixed feasts differ.
For fasting, readings, saints, and feasts, follow your parish calendar.
Fixed feasts and movable feasts
Fixed feasts occur on the same date within a calendar, such as Nativity on December 25. Movable feasts depend on Pascha, such as Palm Sunday, Ascension, and Pentecost.
Why some Orthodox Christians celebrate Christmas in January
Old Calendar Orthodox Christians who celebrate Nativity on Julian December 25 observe that date on January 7 of the civil Gregorian calendar until the calendar difference changes in 2100. They are not celebrating a different event; they are following a different liturgical calendar.
Fixed-feast date examples
For fixed feasts, the visible civil-date difference is often the part people notice first. These examples describe the current 13-day difference for the years 1900 through 2099.
| Feast or commemoration | New Calendar civil date | Old Calendar civil date |
|---|---|---|
| Nativity of Christ | December 25 | January 7 |
| Theophany | January 6 | January 19 |
| Annunciation | March 25 | April 7 |
| Saint George | April 23 | May 6 |
| Dormition of the Theotokos | August 15 | August 28 |
| Saint Nicholas | December 6 | December 19 |
These rows are general fixed-feast examples. Local calendars, transferred celebrations, parish patronal feasts, and pastoral decisions can affect how a parish actually observes a day.
This is not a simple conservative versus liberal map
Calendar practice is tied to history, synods, pastoral decisions, local churches, and inherited parish life. It should not be used to judge the spiritual seriousness of other Orthodox Christians.
Name days and saints
Name days are also affected by calendar use. A saint's feast may be observed on one civil date in a New Calendar parish and 13 days later in an Old Calendar parish during the current period.
This page gives a general orientation. Orthodox jurisdictions and parishes publish their own calendars, and those local calendars should be followed for worship, fasting, saints, and feast observance.