The front end ratio is your monthly housing payment

Monthly housing payment in this case is either your rent or your monthly mortgage if you own a house

Your monthly mortgage is also called P.I.T.I.

P.I.T.I. stands for principal, interest, taxes and insurance.

The back end ratio is your monthly housing payment + all other

As a rule of thumb and depend on your lender, the front end ratio should not exceed 28% while the back end ratio should not exceed 36%

When entering numbers, do not use a slash: "/" or "\"

After you have entered all values, hit calculate and both ratios will be displayed in the big box below: