WHWD

Ovulation Calculator

Estimate an ovulation date and fertile window from the first day of the last period and usual cycle length.

First day of last periodUsual cycle length
Interactive tool

Estimated ovulation date

August 2, 2026

This calendar estimate cannot confirm ovulation and is not reliable contraception.

Estimated fertile window: July 28, 2026 to August 3, 2026. Cycles can vary even when they are usually regular.

These results are educational estimates, not a diagnosis or treatment plan. For personal medical advice, pregnancy guidance, chronic conditions, eating concerns, or medication decisions, speak with a qualified health professional.

Related guides

Read practical articles connected to this calculator.

How to use this result

Use the estimate as a starting point for learning and planning. Recheck the inputs, compare the result with how you feel day to day, and ask a qualified professional before making major changes to diet, exercise, medication, or pregnancy-related decisions.