In the Hanbali school, a separate, specific intention is required for each day of obligatory fasting in Ramadan, and it must be made during the night i.e. between the adhan of Maghrib and the adhan of Fajr .

In the Hanbali school, there is no valid opinion that permits astronomical calculation as method for establishing Ramadan, even for the sake of unifying the Ummah or making scheduling easier.

If the horizon is blocked by clouds or similar obstruction on the 30th night of Shaʿbān, the following day is fasted with the intention that it is Ramaḍān, as a precaution.