Aalamey logoAALAMEY HEALTH
🔒 Calculated in your browser – nothing is sent

Ovulation Calculator

Estimate your ovulation day, fertile window and next period from your last period and cycle length. Free and private.

How to use

Estimate your ovulation day and fertile window from your last period and cycle length. Ovulation usually happens about 14 days before your next period, and the fertile window is the five days before ovulation plus ovulation day and the day after. Cycles vary, so use the result as an estimate.

  1. Enter your details.
  2. Results update instantly.
  3. Adjust the values to see how they change.

More tools

👶Pregnancy Due Date CalculatorEstimate your due date from your last period or conception date, plus your gestational age and trimester dates. Free and private.🤰Pregnancy Week CalculatorFind out how many weeks and days pregnant you are, your trimester and the days left until your due date. Free and private.🔥Calorie CalculatorEstimate your daily calories to maintain, lose or gain weight using the Mifflin-St Jeor equation. Free and private.⚖️Ideal Weight CalculatorSee your ideal weight range using the Devine, Robinson, Miller and Hamwi formulas and the healthy BMI range.📏Body Fat CalculatorEstimate your body fat percentage with the US Navy method from height, neck, waist and hip measurements.💧Water Intake CalculatorEstimate how much water you may need each day from your weight and exercise. Free and private.📈Pregnancy Weight Gain CalculatorSee the recommended pregnancy weight gain for your pre-pregnancy BMI using 2009 Institute of Medicine guidelines.

Frequently asked questions

When am I most fertile?

In the days just before and including ovulation. The calculator marks the fertile window as 5 days before ovulation through 1 day after.

Can I rely on this for contraception?

No. Ovulation timing varies between people and cycles, so this tool is not a method of birth control.

Is it free?

Yes. Everything is free, with no sign-up and no limits.

Is my data stored or sent?

No. Calculations run in your browser and nothing you enter is sent or stored.

Can I rely on these results?

They use standard published formulas and give estimates for general information.

For general information only. This is not medical advice. Talk to your doctor, midwife or dietitian about your own situation.