Programming Interest Calculations Formula in a Software

Dear Mubashir Sb. Assalam o alykum wa rahmatullah wa barakatuh

I am writing this just for a question please answer soonest. Jazak Allah khair.


By profession, I am a software developer and besides my job I undertake freelance projects. One of my prospect, wanted me to develop an application that they will be selling to banks.


The application is actually “Utility Bills Collection System”.

HINT: Besides overall confusion, I suspect the Late Payment Surcharge is calculated based on some INTEREST rate.

So the big question is… if I should go for it or better avoid it.


Ozair Khalid

Dear Brother

Wa alaikum us salam wa Rahmatullah wa Barakatuhu

I’m glad to know that you take care of Allah’s commandments. It is a pleasure to receive your email.

Your mail indicates that you are aware about prohibition of interest and also that of providing any aid to that. As far as the Utility Payment System is concerned, it is lawful because it is simply a deal of purchase and sale. What I know about late payment surcharge, it is a one-time penalty and does not fall under the definition of interest. If it is based on days, then it is interest. You can check with the respective staff of your client.

I think calculation of late payment surcharge will be a minor portion of that system. It is better to avoid that minor portion if possible for you. You know your circumstances better than me. If you can avoid that, its OK. If you cannot due to job problem, do your best to avoid and if no way, seek forgiveness from Allah.


Muhammad Mubashir Nazir

Don’t hesitate to share your questions and comments. They will be highly appreciated. I’ll reply as soon as possible if I know the answer. Send at

Programming Interest Calculations Formula in a Software
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