Free health tools

Period, ovulation & due date calculator

Know when your next period is due, your most fertile days and your estimated due date in seconds. Enter one date and get a clear calendar, simple guidance and the right products for each stage.

  • Private: stays on your device
  • Instant results
  • 100% free

Your cycle

We use these to estimate your upcoming dates.

Average cycle length
28days
From the first day of one period to the first day of the next (usually 21 to 35 days).
Period length
5days

Calculated on your device only. We never store your dates.

Your results will appear here Enter your date and tap Calculate.

Period essentials

Pads, heat packs and care products for more comfortable days.

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These calculators give estimates based on averages, and your cycle can change from month to month. Do not use them as birth control or to diagnose any condition. Talk to your doctor if your cycle is irregular or you have any concern about a pregnancy.

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Frequently asked questions

How is my ovulation day calculated?

Ovulation usually happens about 14 days before your next period starts, so we count back 14 days from your next expected period. Your fertile window is the 5 days before ovulation, the ovulation day and the day after.

Can I use this as birth control?

No. The calculator estimates dates from averages, and ovulation can shift from cycle to cycle. Speak to your doctor or our pharmacist about reliable contraception.

How accurate is the due date?

Your due date is an estimate based on a 40-week pregnancy. Most babies arrive between 37 and 42 weeks, and your doctor may adjust the date after an ultrasound scan.

What if my periods are irregular?

Enter your average cycle length over the last 3 to 6 months. If your cycles vary a lot, results are less accurate, so ovulation tests and a check-up with your doctor can help.