Key points
- Your aadat is the length of your haiz and of your purity in your last valid cycle.
- A single valid cycle establishes or changes the habit (the relied-upon position).
- The habit only decides the ruling when bleeding exceeds 10 days.
What aadat means
Aadat (عادت) is your habit: how many days your last valid haiz lasted, and how many days of purity came before the next one. A woman with a habit of "7 and 23" bled for 7 days and was then pure for 23.
When the habit matters
As long as the bleeding stops within 10 days, the habit does not change the ruling: all of the bleeding is haiz. The habit becomes decisive only when bleeding goes beyond 10 days. Then you go back to your habitual days: those are haiz, and everything else is istihaza.
How the habit changes
A habit is established, and changed, by one valid cycle. You do not need to see the new pattern three times. If your habit was 6 days and this time you bled for 8 days and then stopped, your habit is now 8.
When bleeding goes beyond 10 days and only part of it falls on your habitual days, the habit can change in two ways:
- In number: if at least 3 of your habitual days had blood, those days are haiz and your habit becomes that number of days, at the same time of the month.
- In timing: if fewer than 3 of your habitual days had blood, your habitual number of days is counted from the start of the bleeding instead.
The Haiz Calculator shows which of these applies to your dates.
After childbirth, miscarriage or medication
Pregnancy, birth, hormonal contraception and illness can all change your cycle. The rules do not change: the most recent valid cycle is your habit. If you have no clear habit at all, or have forgotten it, the rulings become detailed and you should ask a scholar.
Keep a record
Because one cycle can change your habit, note the start and end time of every period and the clean days between them. See how to track your cycle for worship.
This guide is educational and follows mainstream Hanafi positions. For your own situation, please consult a qualified scholar. See the disclaimer, the glossary and how rulings are worked out.