Answer:
(Fatwa: 1926/D=416/K=1431)
(1) Using credit card is lawful on condition that the payment of issued bills is made within the fixed period without levying any interest; because it is haram to pay interest.
(2) In case of delay the two percentage which one has to pay as penalty is interest and thus unlawful. If the whole amount is paid and each month without delay, the credit cards of these companies may be used.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
