For home-owners who are looking at refinancing their mortgage loans, or simply at the amount of loan they have to pay to the banks when the interests fluctuates,


is a very useful website that can assist you. Extracted from the site, here is  very brief overview of the types of calculator which you can use:

Mortgage Payment Table Calculator

and so on. This is an American based site. For the Singapore based Banks, the mortgage calculator is as follows: 


Hope you find it useful. :)