- Obligatory fast, like during the month of Ramadan;
- Mustaḥabb fast, like during the months of Rajab and Sha'bān;
- Makrūh fast, like on the day of 'Āshūrā;
- Ḥarām fast, like on Eid ul-Fir (the first of Shawwāl) and Eid ul-Adha (the tenth of Dhi al-Hajjah).

Obligatory fast
 Obligatory fasts are as follows:
- Fast during the month of Ramadan;
- Qaḍā’ fast;
- Kaffārah fast;
- Parents' qaḍā’ fast;
- Mustaḥabb fast which became obligatory due to nadhr, 'promise', or 'swear';
- Fast on the third day of i'tikāf
- Fast instead of slaughtering in tamattu' haj .

* If a pilgrim is not able to slaughter and cannot borrow money, he should, instead, fast for ten days, of which three days is kept during haj and seven days in his waṭan.

Fast on the day of 'Āshūrā
4. Is it allowed to fast on the day of 'Āshūrā?
A: It is makrūh.

Silence Fast
5. I heard that silence fast is ḥarām while some say it is ḥalāl in case of nadhr, is it true?
A: It is ḥarām.

Fast of One's spouse/child
6. Naming ḥarām fast, they include: fast of the wife in case it violates the right of the husband and fast of a child in case it hurts/annoys the parents. Do they apply in mustaḥabb fasts only, or they include obligatory fast without shortage of time?
A: It does not include obligatory fasts.