--- title: "About Period Calc: Who Makes It and Why" description: "Who makes Period Calc, why it shows the Hijri date on every day, how its predictions work and how it keeps your cycle data private." url: https://periodcalc.app/about/ lang: en --- # About Period Calc A private, year-round period tracker and planner for Muslim women, made by one independent developer. ## 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](https://periodcalc.app/period-calculator/) and [ovulation calculator](https://periodcalc.app/ovulation-calculator/) use. The [due date calculator](https://periodcalc.app/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](https://periodcalc.app/privacy/). ## 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](mailto:hossam.hamoda@gmail.com), or see [Support](https://periodcalc.app/support/) for common fixes. ## Get reminders before your next period **Period Calc** for iPhone learns from your own cycles and reminds you two days before your period — discreetly, with no details unless you turn them on. - The Hijri date on every calendar day - Your fasting days, every month - A PIN and Face ID lock, and no account [Download on the App Store](https://apps.apple.com/app/id6814298894) ## Free calculators - [Period calculator](https://periodcalc.app/period-calculator/): Your next six periods, fertile days and ovulation, in Gregorian and Hijri dates. - [Ovulation calculator](https://periodcalc.app/ovulation-calculator/): Your fertile window and ovulation day for the next three cycles. - [Due date calculator](https://periodcalc.app/due-date-calculator/): Your due date, how many weeks pregnant you are and your trimester. - [Pregnancy week calculator](https://periodcalc.app/pregnancy-week-calculator/): How many weeks and days pregnant you are, your trimester and due date, from your last period or your due date. - [Conception date calculator](https://periodcalc.app/conception-date-calculator/): Count back from your due date to the days you most likely conceived: an estimate, not an exact day. - [Pregnancy test date calculator](https://periodcalc.app/pregnancy-test-date/): Shows the day your next period is due. The NHS says most tests can be done from the first day of a missed period. Predictions are estimates, not medical advice or a diagnosis, and not a method of contraception. The prayer & purity guide gives the general rules of the four schools. It is not a fatwa — for your own case, ask someone whose knowledge you trust. This website uses no cookies and no analytics. The calculators run in your browser, and nothing you type is sent anywhere.