# Calculating monthly fee based on interest and time

Hi, is it possible to create a formula to calculate the monthly rate from a loan with a fixed period and interest? Similar like:

Oh thats a challenging one. You can add a ‘basic formula’ column in your table and enter the high school formula which all of us were shown… but clearly I would fail if re-tested.

Tim would know how to finish that formula … this kind of thing is right up his street.

Hi @Shumon, thanks for the reply. Another option would be (loan term is 360 months) with a loan of 100.000 EURO

• Monthly interest = Annual interest / 12

• Monthly payment = (monthly interest / (1-((1 + monthly interest) ^ -360 ))) * 100.000 EURO = 537 EURO.
I haven’t checked yet whether the POWER math function can handle this type of calculation in Tadabase.

Hi Martin,

Oh i see, that symbol is a Power, i didnt know what it was … anyway, as you can see from my screenshot that is where i got stuck. I’ll have a look to see if tb does the power function…

this passes validation but im not sure where to put the brackets for power.

({MonthlyInterest} / (1-((1 + {MonthlyInterest}) ^-360))) * ({LoanAmount})

if you correct this formula for me by putting the brackets in the right place then it might work.
({MonthlyInterest} / (1-((1 + {MonthlyInterest}) POWER()-360))) * ({LoanAmount})

@Shumon , when the power function is used correctly it works POWER(monthly interest, -360).