Calculating irregular loans

[Mike Jones]

Hello, I am a beginner lender, although I have my uncle guiding me who is more experienced. I am looking for a program to calculate my irregular loans. So far, the programs I have found do an inadequate job with monthly compounding. E.g. if there are two payments instead of one spaced within a month the program will compound interest twice during that month instead of once. Does anyone know of a program that can do monthly compounding on irregular loans without over-compounding? Or can someone explain to me how to calculate this out manually. I just want the calculations done properly so I'll be covered if I ever end up in court. Thanks.