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Pregnancy / Cycle

Cycle and ovulation calculator

Estimate your fertile window, ovulation date, and due date from a recent period start.

Last period start

Cycle length (days)

Luteal phase length (days)

Ovulation -

Fertile window -

Due date -

Cycle timeline

Luteal phase: 14 days

Second trimester starts: -

Third trimester starts: -

Health

Estimation note

This estimate is based on a standard 28-day cycle and is intended for general planning. Real menstrual tracking varies from person to person.

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Good fit for fertility tools, clinics, or wellness brands.