Cycle and fertility

Tools to estimate period timing, ovulation, fertile window, and conception timing. Each calculator links to its methodology.

Last updated April 25, 2026

Tools

Predict your next period and see your cycle on a calendar.

Estimate your ovulation day and fertile window from your LMP and cycle length.

Estimate when you conceived from a due date or LMP, with cycle adjustment.

Review assumptions, cycle inputs, and source notes for the Period Calculator.

Review fertile-window assumptions and source notes for the Ovulation Calculator.

Review conception-window assumptions and source notes for the Conception Calculator.