What you will find here
Period Calc is a period tracker and planner for iPhone, made for Muslim women. The calculators on this site work out dates such as your next period, fertile days, due date and pregnancy week from your own dates, in the Gregorian and Hijri calendars. Nothing you type leaves your browser.
The guides are plain-English answers to the questions behind those dates. Start with a calculator for your own dates, then read a guide for what is usual and when to ask a doctor.
How the guides are made
Each guide starts with a short answer to one question, then explains. The health guides link the health numbers to the NHS (the UK’s National Health Service), ACOG (the American College of Obstetricians and Gynecologists) or the WHO (the World Health Organization) page they come from. They also say when to see a doctor.
Hossam Hamouda, the developer of Period Calc, writes the guides. Those organisations have not reviewed the health guides, and neither has a doctor. The guides give general information, not medical advice, and they are not a method of contraception.
Looking for answers about the app instead? See the FAQ or Support.