I am having a hard time on figuring out how to calculate what the actual interest rate of a loan would be when there is a commission attached to it.

If I take out a loan for $45,000,000 at 5% over 300 months (25 years) and had to pay a financing company $1,250,000 (~2.78%) in commission at closing, then how should I account for the commission in the rate for the loan?

Should I look at it as an addition to the loan, as if it was $46,250,000 over 300 months or should I take the 25 year amortized value of $1,250,000 and add the percent difference to the 5% interest rate?

Normally I'm good at finance, but w/ the comission thrown into the mix it's throwing me off my financial game so I was hoping someone on this board could shine some light on this for me.