Ovulation Calculator
Estimate your most fertile days and ovulation window based on your menstrual cycle.
Local-first
Fertile window
—
Ovulation
—
How this tool works
What it accepts, how to use it, and where your input is processed.
Show GuideHide Guide
How this tool works
What it accepts, how to use it, and where your input is processed.
Show GuideHide Guide
Estimate your fertile window from cycle length. Ovulation is typically about 14 days before the next period.
Most cycles range from 25 to 35 days. This is an estimate, not a diagnosis or a method of birth control.
Need an extra feature or found an edge case?Send Feedback
Related tools
Open after you finish the primary task.
ShowHide
Related tools
Open after you finish the primary task.
BMR Calculator
MathCalculate your Basal Metabolic Rate (BMR) to understand your body's energy needs at rest.
Open tool
Water Intake Calculator
MathCalculate how much water you should drink daily based on your weight and activity level.
Open tool
Body Fat Calculator
MathEstimate your body fat percentage using the US Navy method based on your body measurements.
Open tool