Establishing a Veset Kavua: Graphic Calendars

A woman establishes a veset kavua if her cycle follows a consistent and predictable pattern for three consecutive periods. The laws of a veset kavua are explained in the article on Veset Kavua. This article presents graphic calendars to illustrate how such a veset is established.

The most common forms of the veset kavua are the veset hachodesh (date of the Hebrew month) and the veset haflagah (interval):

Veset Hachodesh

A woman establishes a veset hachodesh kavua when three consecutive menstrual periods begin on the same date of the Hebrew month during the same onah (daytime or night-time), as in the following example.

Nissan

A woman begins to menstruate on 15 Nissan during the day.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
1	2	3	4	5	6	7
8	9	10	11	12	13	14
15	16	17	18	19	20	21
22	23	24	25	26	27	28
29	30

Iyar

Her next menses begin on 15 Iyar during the day.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
		1	2	3	4	5
6	7	8	9	10	11	12
13	14	15	16	17	18	19
20	21	22	23	24	25	26
27	28	29

Sivan

Her next menses begin on 15 Sivan during the day. She has now begun to menstruate on the 15th of the month during the day for three consecutive months. She has established a veset kavua for yom hachodesh.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
			1	2	3	4
5	6	7	8	9	10	11
12	13	14	15	16	17	18
19	20	21	22	23	24	25
26	27	28	29	30

Tammuz

She observes her veset kavua on 15 Tammuz during the day .

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
					1	2
3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	18	20	21	22	23
24	25	26	27	28	29

Veset Haflagah

A veset haflagah is established when four consecutive menstrual periods are separated by three equal intervals. The last three menstrual periods must all begin during the same onah, as in the following example.

Nissan

A woman begins to menstruate on 15 Nissan during the day.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
1	2	3	4	5	6	7
8	9	10	11	12	13	14
15 (1)	16 (2)	17 (3)	18 (4)	19 (5)	20 (6)	21 (7)
22 (8)	23 (9)	24 (10)	25 (11)	26 (12)	27 (13)	28 (14)
29 (15)	30 (16)

Iyar

Her next menses begin 28 days later, on 12 Iyar during the day.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
		1 (17)	2 (18)	3 (19)	4 (20)	5 (21)
6 (22)	7 (23	8 (24)	9 (25)	10 (26)	11 (27)	12 (28=1)
13 (2)	14 (3)	15 (4)	16 (5)	17 (6)	18 (7)	19 (8)
20 (9)	21 (10)	22 (11)	23 (12)	24 (13)	25 (14)	26 (15)
27 (16)	28 (17)	29 (18)

Sivan

Her next menses begin 28 days later, on 10 Sivan during the day.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
			1 (19)	2 (20)	3 (21)	4 (22)
5 (23)	6 (24)	7 (25)	8 (26)	9 (27)	10 (28=1)	11 (2)
12 (3)	13 (4)	14 (5)	15 (6)	16 (7)	17 (8)	18 (9)
19 (10)	20 (11)	21 (12)	22 (13)	23 (14)	24 (15)	25 (16)
26 (17)	27 (18)	28 (19)	29 (20)	30 (21)

Tammuz

Her next menses begin 28 days later, on 7 Tammuz during the day.

She has now menstruated at 28-day intervals, beginning during the day, for three consecutive months. She has established a veset kavua for the haflagah.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
					1 (22)	2 (23)
3 (24)	4 (25)	5 (26)	6 (27)	7 (28=1)	8 (1)	9 (2)
10 (3)	11 (4)	12 (5)	13 (6)	14 (7)	15 (8)	16 (9)
17 (10)	18 (11)	19 (12)	20 (13)	21 (14)	22 (15)	23 (16)
24 (17)	25 (18)	26 (20)	27 (21)	28 (22)	29 (23)

Av

She observes her veset kavua after a 28-day interval, on 5 Av.

Rishon	Sheini	Shlishi	Revi'i	Chamishi	Shishi	Shabbat
						1 (24)
2 (25)	3 (26)	4 (27)	5 (28)	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25	26	27	28	29
30