Translating Dates between the

Republican and Gregorian Calendars

To convert a date in the Republican calendar to a Gregorian date

Suppose one wishes to find the Gregorian equivalent of 5 Germinal Year VII.

Find the month “Germinal” in the leftmost column. Notice that the Gregorian month equivalent to Germinal was March.
Find year 7 in the top row.
Follow the column headed “7” down to the Germinal row. The number in the box is the Gregorian date of the first day of Germinal, so March 21. To find the 5th of Germinal, we need to add 4, so 5 Germinal was March 25.
The column also shows that Germinal Year 7 was in the Gregorian year 1799. So 5 Germinal Year 7 would be 25 March 1799.

Year in Republican calendar:		2	3	4	5	6	7	8	9	10	11	12	13	14
Republican month	Gregorian month	1793	1794	1795	1796	1797	1798	1799	1800	1801	1802	1803	1804	1805
Vendémiaire	Sept.	22	22	23	22	22	22	23	23	23	23	24	23	23
Brumaire	October	22	22	23	22	22	22	23	23	23	23	24	23	23
Frimaire	Nov.	21	21	22	21	21	21	22	22	22	22	23	22	22
Nivôse	Dec.	21	21	22	21	21	21	22	22	22	22	23	22	22
		1794	1795	1796	1797	1798	1799	1800	1801	1802	1803	1804	1805	1806
Pluviôse	Jan.	20	20	21	20	20	20	21	21	21	21	22	21	21
Ventôse	Feb.	19	19	20	19	19	19	20	20	20	20	21	20	20
Germinal	March	21	21	21	21	21	21	22	22	22	22	22	22	22
Floréal	April	20	20	20	20	20	20	21	21	21	21	21	21	21
Prairial	May	20	20	20	20	20	20	21	21	21	21	21	21	21
Messidor	June	19	19	19	19	19	19	20	20	20	20	20	20	20
Thermidor	July	19	19	19	19	19	19	20	20	20	20	20	20	20
Fructidor	August	18	18	18	18	18	18	19	19	19	19	19	19	19
Complément	Sept.	17	17	17	17	17	17	18	18	18	18	18	18	18

To convert a date in the Gregorian calendar to a Republican date
Gregorian year:		1793	1794	1795	1796	1797	1798	1799	1800	1801	1802	1803	1804	1805
Year of the Republic		1	2	3	4	5	6	7	8	9	10	11	12	13
Jan.	Nivôse	12	12	12	11	12	12	12	11	11	11	11	10	11
Feb.	Pluviôse	13	13	13	12	13	13	13	12	12	12	12	11	12
March	Ventôse	11	11	11	11	11	11	11	10	10	10	10	10	10
April	Germinal	12	12	12	12	12	12	12	11	11	11	11	11	11
May	Floréal	12	12	12	12	12	12	12	11	11	11	11	11	11
June	Prairial	13	13	13	13	13	13	13	12	12	12	12	12	12
July	Messidor	13	13	13	13	13	13	13	12	12	12	12	12	12
August	Thermidor	14	14	14	14	14	14	14	13	13	13	13	13	13
Sept.	Fructidor	15	15	15	15	15	15	15	14	14	14	14	14	14
length of Complément in days		5	5	6	5	5	5	6	5	5	5	6	5	5
Year of the Republic		2	3	4	5	6	7	8	9	10	11	12	13	14
Oct.	Vendémiaire	10	10	9	10	10	10	9	9	9	9	8	9	9
Nov.	Brumaire	11	11	10	11	11	11	10	10	10	10	9	10	10
Dec.	Frimaire	11	11	10	11	11	11	10	10	10	10	9	10	10

*Bear in mind that Jours Complément followed Fructidor, so running beyond the 30 days of Fructidor takes one into Jours Complément before Vendemiaire.