Interest rates calculator

Hi,

My boss needs a calculator for loan applicants. He wants the loan applicants to be able to see what the interest rate will be if they get a loan from him.

I will need to add this onto a Wordpress and Squarespace website, if it's too complx then I would need you to do it for me.

Have included below the formulas he gave me. Feel free to ask any questions if anything is unclear and I will pass them on to him.

Below is an example of all the algorithm that needs to go into a calculator:
0% - 59% Loan to Costs is 7%
60% - 69% Loan to Costs is 8%
70% - 79% Loan to Costs is 9%
80% - 89% Loan to Costs is 10%
90% - 95% Loan to Costs is 11%
Or
0% - 59% Loan to Costs is 4.25% plus 30/70 profit split in your favour
60% - 69% Loan to Costs is 4.5% plus 35/65 profit split in your favour
70% - 79% Loan to Costs is 5% plus 40/60 profit split in your favour
80% - 89% Loan to Costs is 5.25% plus 45/65 profit split in your favour
90% - 95% Loan to Costs is 5.5% plus 50/50 profit split

Thank you