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Last period started in January: when is the next one?

Find the day your last period started in the left column and your usual cycle length along the top. The date where they meet is the estimated start of your next period. January has 31 days.

With a 21-day cycle, a period that starts on January 1 to 10 is followed by the next one before January ends. With a 28-day cycle, a period that starts on January 1 to 3 is followed by the next one before January ends.

Last start21-day cycle25-day cycle28-day cycle30-day cycle32-day cycle35-day cycle
Jan 1Jan 22Jan 26Jan 29Jan 31Feb 2Feb 5
Jan 2Jan 23Jan 27Jan 30Feb 1Feb 3Feb 6
Jan 3Jan 24Jan 28Jan 31Feb 2Feb 4Feb 7
Jan 4Jan 25Jan 29Feb 1Feb 3Feb 5Feb 8
Jan 5Jan 26Jan 30Feb 2Feb 4Feb 6Feb 9
Jan 6Jan 27Jan 31Feb 3Feb 5Feb 7Feb 10
Jan 7Jan 28Feb 1Feb 4Feb 6Feb 8Feb 11
Jan 8Jan 29Feb 2Feb 5Feb 7Feb 9Feb 12
Jan 9Jan 30Feb 3Feb 6Feb 8Feb 10Feb 13
Jan 10Jan 31Feb 4Feb 7Feb 9Feb 11Feb 14
Jan 11Feb 1Feb 5Feb 8Feb 10Feb 12Feb 15
Jan 12Feb 2Feb 6Feb 9Feb 11Feb 13Feb 16
Jan 13Feb 3Feb 7Feb 10Feb 12Feb 14Feb 17
Jan 14Feb 4Feb 8Feb 11Feb 13Feb 15Feb 18
Jan 15Feb 5Feb 9Feb 12Feb 14Feb 16Feb 19
Jan 16Feb 6Feb 10Feb 13Feb 15Feb 17Feb 20
Jan 17Feb 7Feb 11Feb 14Feb 16Feb 18Feb 21
Jan 18Feb 8Feb 12Feb 15Feb 17Feb 19Feb 22
Jan 19Feb 9Feb 13Feb 16Feb 18Feb 20Feb 23
Jan 20Feb 10Feb 14Feb 17Feb 19Feb 21Feb 24
Jan 21Feb 11Feb 15Feb 18Feb 20Feb 22Feb 25
Jan 22Feb 12Feb 16Feb 19Feb 21Feb 23Feb 26
Jan 23Feb 13Feb 17Feb 20Feb 22Feb 24Feb 27
Jan 24Feb 14Feb 18Feb 21Feb 23Feb 25Feb 28
Jan 25Feb 15Feb 19Feb 22Feb 24Feb 26Mar 1
Jan 26Feb 16Feb 20Feb 23Feb 25Feb 27Mar 2
Jan 27Feb 17Feb 21Feb 24Feb 26Feb 28Mar 3
Jan 28Feb 18Feb 22Feb 25Feb 27Mar 1Mar 4
Jan 29Feb 19Feb 23Feb 26Feb 28Mar 2Mar 5
Jan 30Feb 20Feb 24Feb 27Mar 1Mar 3Mar 6
Jan 31Feb 21Feb 25Feb 28Mar 2Mar 4Mar 7

The table is worked out for 2027. In a leap year (the next is 2028), an estimate that crosses February 29 lands one day earlier than shown.

Periods often start a few days either side of an estimate. Every date here is an estimate from a typical cycle length. It is not birth control and it is not medical advice.

Estimate the next six periods with your own cycle length

Log the first day of each period in Isla and it keeps the next estimate, a range and the calendar up to date on your iPhone. No account and no ads.

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