Ovulation Calculator

Parameters

First day of last period

Cycle length (days)

Period length (days)

Cycle 1

Period19 October — 23 October

Fertile window28 October — 3 November

Ovulation day2 November

Cycle 2

Period16 November — 20 November

Fertile window25 November — 1 December

Ovulation day30 November

Cycle 3

Period14 December — 18 December

Fertile window23 December — 29 December

Ovulation day28 December

Ovulation is estimated as 14 days before cycle end. Fertile window — 5 days before and 1 day after ovulation. Accuracy is lower with irregular cycles.