A wide variety of websites have online financial calculators that let you input your loan amount, interest rate, and loan term. The calculator will tell you what your monthly payments will be.
If you do not always have easy access to the Internet, you can do the same calculations in Microsoft Excel. Create a spreadsheet as follows. Column A has the information you will enter on your spreadsheet for each row.
You must enter the information in exactly the order described; otherwise, you will not arrive at the right monthly payment.