2. How is the annual rate converted to the rate that is commensurate with the calculation frequency? Often, rate/365, rate/12 or rate/2. But in many countries, (1+rate)^(1/f) - 1, where "f" is 365, 12 or 2. And then there is Canada (sigh).

The link that you provided shows $475,140.61 for total interest.

The "calculator" that I provided (response #2) shows the same result if we replace the formula in C4 with =(1+B4)^(1/2)-1 -- an option that I mentioned already.

Apparently, that is what calculator.net means by choosing the option Compound "Annually (APY)", as you did.

However, that is not correct for a US loan that conforms to the "Truth In Lending" regulations. For such US loans, the interest rate should be stated as a __simple__ annual rate, not a compounded annual rate (APY).

Since calculator.net is based in Texas (US), I find it odd that it does not at least provide an option for specifying a simple annual rate. Perhaps it does, and I'm not seeing it.

Oddly, we do get the same total interest with calculator.net that I calculated originally -- $482,577.45 with =B4/2 in C4 -- by choosing the option Compound Semi-Annually at calculator.net.

Using common-sense interpretation of English, I would have expected the results to be just the opposite for the two "compounding" options.

I should say: for the assumptions that I had to make. **You have not answered any of my questions.**

And you __still__ have not done so. I expect you to answer those questions based the terms of the actual (real-life) loan.

Since you cannot follow directions, this will be my last comment on the subject. Good luck!