月經週期計算器

追蹤月經週期並預測下次月經和排卵日

First day of last period

Average cycle length (days)

Estimated next period

2026年8月18日

Estimated ovulation

2026年8月4日

Estimated fertile window

2026年7月30日 – 2026年8月5日

This is a calendar estimate. Ovulation can vary from cycle to cycle and estimates are less reliable with irregular cycles, lactation, perimenopause, illness, or medicines. Do not use it for contraception, pregnancy confirmation, or infertility diagnosis.

Seek medical advice for a sudden cycle change, no period for 3 months when not pregnant, very heavy bleeding, fainting, or severe pelvic pain.