How to calculate monthly payment for loan amount?

I am trying to calculate what the payments would be 5, 12, 20-year loan with different amounts like this site http://finance.savecal.info/ 

I know its possible in jotform, this guy has done it but I don't know how https://form.jotformeu.com/60561555261352 

You can perform a calculation inside of a form, with the Form Calculation widget and conditional logic.

How to Perform Form Calculation Using a Widget

How to Insert Text or Calculation into a Field Using Conditional Logic

The form you provided cannot be cloned, so I would suggest you to try to set up a calculation inside of your form using the guides I provided above. 

Most likely you will also have to assign calculation values to some fields, so I would suggest you to check this guide as well:

How to Assign Calculation Value

If you have any issues to set up a calculation inside of your form, let us know. 

If I have the total loan number amount and the number of payments and the APR interest rate.

What formula do i use in Jotform to find monthly payment?

How is this one done? https://form.jotformeu.com/60561555261352

This is the formula the user implemented on the total of his form: 

You may also clone the form and inspect what the user has done there, this guide will help you cloning it: https://www.jotform.com/help/42-How-to-Clone-an-Existing-Form-from-a-URL 

The guides my colleague provided should also help to understand how to add the needed elements and perform the calculations. 

If you have questions, let us know. 

It's not that simple because it's APR annual percentage rate that determines the monthly payment not just total balance / payments. 

So I'm assuming you have to convert the interest rate into a decimal point save it and then the years / the months save it and then calculate what the per month interest rate would be plus that or some kind of similar calculation. 

It would have been easier if I could have copied and cloned the one I'm given as a sample but it shows Unauthorized request. You do not have access to this form 

Ok, the user seems to be using the "pow()" function, you will find more details about it here: https://www.jotform.com/help/267-Form-Calculation-Math-Function-Reference 

I have also a form where the formulas are implemented, you may clone my form using this link: https://form.jotform.com/82846465625972 

This way you may see the formulas implemented on the current calculations. 

I hope this helps.