Period Calculator
Estimate your next period, ovulation date, and most fertile days — instantly and for free.
JUNE, 2026
Low chance of getting pregnant
Period
Approximate day of ovulation
Higher chance of getting pregnant
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Your Estimated Dates
How to Use the Period Calculator
Our period calculator helps you predict your menstrual cycle with ease. Enter three pieces of information — the first day of your last period, your average cycle length, and how many days your period typically lasts — then tap Calculate.
What the Calendar Colors Mean
- Red dot – Period days: Days when bleeding is most likely.
- Pink dot – Ovulation day: The approximate day your body releases an egg.
- Purple dot – Fertile window: Days with a higher chance of conception.
- Dark dot – Low-fertility days: Days when pregnancy is unlikely.
Understanding Your Menstrual Cycle
A typical menstrual cycle lasts between 21 and 35 days, measured from the first day of one period to the first day of the next. Ovulation generally occurs about 14 days before your next expected period — but this varies from person to person and cycle to cycle.
Frequently Asked Questions
How accurate is this period calculator?
This tool provides estimates based on average cycle patterns. Results are most accurate when your cycles are regular. Stress, illness, diet, and medications can shift your cycle. Always consult a healthcare provider for medical advice.
What is the fertile window?
The fertile window is typically the 5 days before ovulation plus ovulation day itself. This is when pregnancy is most likely. Sperm can survive inside the body for up to 5 days, while an egg is viable for only 12–24 hours after release.
Can I use this calculator to avoid pregnancy?
This calculator is an educational tool only and should not be used as a form of contraception. Natural family planning methods have high failure rates and should always be discussed with a qualified healthcare professional.
My cycle is irregular — can I still use this?
Yes, but results will be less precise. Try using the average of your last 3–6 cycle lengths as your cycle length input. If your cycles vary by more than a week, consider speaking with a healthcare provider to investigate potential causes.
Disclaimer: This period calculator is for informational purposes only and does not constitute medical advice. Predictions are estimates and may not reflect your actual cycle. Consult a qualified healthcare provider for personal medical guidance.