Hello all

I've been working on a loan schedule application

I’ve finished the scripts needed to create a loan schedule for the four types of loans we use over here.

Well five types it, if one includes bubble loans.

===

Now I need to calculate APR for these different types of loans

I know that APR equals the cost of the loan divided by its original payment value.

Not sure i’m wording this correctly but at least its: APR = cost / netto loan amount, probably calculated at the present value of each payment involved.

I have looked at the formulas for APR as depicted on https://en.wikipedia.org/wiki/Annual_percentage_rate and in current EU regulations

===

As usual I had no idea what I was doing when I started out on this and thought I could just turn the formula for APR.

However it seems it's not possible to turn the formula for APR so people are using Excel and Goal seek to solve the equations involved.

The EU provides an Excel based calculator which uses password protected scripts and has no intention of providing an open version. To protect the calculators integrity. Also it is up to the member nations to provide the details needed to use the formulas.

===

Can anyone here explain to me what is involved if I want to write a script to solve the needed calculations in Filemaker?

TIA

Hans

As it turns out the bisection and Newton Rapes methods are but two of a family of root solving methods that can be used to solve this issue. To solve these types of calculations one needs to re-create the goal seek functionality as offered by Excel.