How to calculate the principla in an amortization schedule

[RMSistight]

How do you calculate the principal in an amortization schedule? I can't seem to figure it out.

 

[minendo]

Multiply by 0.

 

[robh23]

assuming interest is end of year,

start balance of year 1 x interest rate in loan = interest payment in year one.

principle red in year one = loan payment - interest payment.

year 2 start principle balance = previous years pricinple - previous year's principle payment.

do it on excel easy. i think there is a formula as well.

 

[RossMAN]

Or you can use a loan calculator with ammortization