Financial: Savings plan calculation - Printable Version +- HP Forums ( https://www.hpmuseum.org/forum)+-- Forum: HP Calculators (and very old HP Computers) ( /forum-3.html)+--- Forum: HP Prime ( /forum-5.html)+--- Thread: Financial: Savings plan calculation ( /thread-10747.html) |

Financial: Savings plan calculation - cds - 05-16-2018 09:11 AM
Dear all, I struggle on an approach to solve the following financial calulation: Given is a saveings plan with a fixed time t[yr], interest rate, static monthly investment and - here comes my issue - an annual bonus which depends on the annual invested money (and so is constant during the whole contract). I'm now looking on a solution how to calculate the needed interestrate to achive the desired final capital at the end of the contract. Without this "annual bonus" it is a no-brainer, but with I'm kind of stuck. Any hints for me? Regards Carsten. RE: Financial: Savings plan calculation - cortopar - 05-16-2018 08:02 PM
Pseudo Pascal-ish code for the brute force method... Code:
Now this is going to return the interest at which balance exceeds goal. To get it exact would need additional processing at finer precision. I’m sure there’s a formulaic way to solve this easier, but it exceeds my math abilities. Edited to Prime-compliant HP-PPL. Tested on my Prime. It is slow as you’d expect. It could be sped up by providing or calculating a starting guess and larger increment before refining. RE: Financial: Savings plan calculation - KeithB - 05-21-2018 04:49 PM
Sounds tailor-made for the spreadsheet. RE: Financial: Savings plan calculation - cds - 05-23-2018 08:28 AM
Well, an formularic approach would be exactely what I would be looking for. I can't believe that this can only be solved by an iterative solution .... RE: Financial: Savings plan calculation - KeithB - 05-23-2018 02:06 PM
Just use a separate calculation for the bonus compounded annually. I.e. (compounded value of monthly payments) + (compounded value of bonus) The reason to suggest the spreadsheet was for generality. |