Who makes Period Calc
Period Calc (حاسبتي in Arabic) is made by Hossam Hamouda, an independent app developer. He designs and builds the app and this website, and support emails go straight to him.
He is not a doctor or a religious scholar. The calculator pages explain the standard calendar method and list the health organisations whose guidance they follow. The prayer & purity guide in the app gives the general rules of the four schools — it is not a fatwa.
Why it exists
Many Muslim women plan their month with two calendars at once: the Gregorian one for work and school, and the Hijri one for fasting, prayer and family occasions. Period Calc puts both on one calendar, marks the days your period is expected and lists your fasting days every month of the year.
It is also built for privacy. Cycle data is among the most personal data there is, so the app needs no account, shows no ads and keeps what you record on your phone.
How the predictions work
The app averages your last six logged cycles; until you have logged two periods, it uses the cycle length you chose. Ovulation is estimated 14 days before your next expected period, and your fertile window runs from 5 days before ovulation to 1 day after. This is the calendar method, the same rule the free period calculator and ovulation calculator use. The due date calculator follows Naegele’s rule: 280 days from the first day of your last period.
Predictions are estimates. They are not medical advice or a diagnosis, and not a method of contraception.
Privacy principles
- No account, no sign-in and no ads.
- Your cycle data stays on your phone, and we never receive it.
- The app sends anonymous usage steps — never your health data — and you can turn them off in Settings.
- This website uses no cookies and no analytics, and its calculators run in your browser.
The details are in the Privacy Policy.
Languages
The app is available in more than 50 languages.
This website is available in the languages listed at the bottom of every page.
Contact
Questions, ideas or a problem? Email hossam.hamoda@gmail.com, or see Support for common fixes.