Any formula to calculate the initial payment for a 5/1 arm? (interest rate, fees)

[howard555]

Any formula to calculate the initial payment for a 5/1 arm?

looking for the formula, not an online calculator.

Thanks.

[dad2jules]

Initial payment is determined by initial interest rate which is stated in your Note, it is not something that you calculate.

[acegolfer]

OP,

Do you use Excel?

Then use this function =pmt( ).

Instead, if you want an analytical function, I can provide you with one.

[howard555]

Originally Posted by acegolfer

OP,

Do you use Excel?

Then use this function =pmt( ).

Instead, if you want an analytical function, I can provide you with one.

yes, that would be helpful, thanks.

Asking for someone else if that is ok. Here are some formulas but they do not make reference to 5-1 arms.
http://www.mtgprofessor.com/formulas.htm
Their client is " getting something a bit different and the formula the client gave is nothing like the one above.

[acegolfer]

Originally Posted by howard555

yes, that would be helpful, thanks.

Asking for someone else if that is ok. Here are some formulas but they do not make reference to 5-1 arms.
http://www.mtgprofessor.com/formulas.htm
Their client is " getting something a bit different and the formula the client gave is nothing like the one above.

The formula in the link is correct and also applies to 5/1 ARMs for the first 5 years.

[howard555]

thanks.

[howard555]

Originally Posted by acegolfer

The formula in the link is correct and also applies to 5/1 ARMs for the first 5 years.

Here is the latest:
The client is using their own program that they have tried on SQL.

arm_bal = new_loan_amt_orig - totprin
new_loan_amt_orig = new_loan_amt
new_loan_amt=( APR_CALC_AMT + APR_CALC_FEES + one_mo_int) + ((POINTS / 100)*APR_CALC_AMT)
one_mo_int=(APR_CALC_AMT * rate) / 1200
totprin = totprin + currentprin
currentprin = arm_pandi – currentint
arm_pandi = PnI_pmt
PnI_pmt =(new_loan_amt * (rate/1200))/(1-(1+(rate/1200))**(-Apr_term))
currentint = new_loan_amt*calcint
calcint = (rate / 1200)
fully_ndx_rate = Apr_margin + APR_index (both fields in the file)
adj_period = APR_TERM - new_arm_period

They think it is a different formula than mortgage professor.
(I was asking for them, so the formulas are greek to me)