How do you determine the risk-free interest rate for the Black-Scholes option calculator?
I heard you use U. S treasury bills but I went to their site and I get quotes from 4, 13, 26, and 52 weeks, and then I get quotes like . 18, . 22, . 40, . 56 respectively whereas it appears that example risk-free rates are quoted at 4. 7% ish. This confuses [...]

