Function caplet(Sett_d As Date, from_d As Date, to_d As Date, Strike As Double, vola As Double, Date_v As Object, PV_v As Object, underrate As Double) As Double
' Valuation of caplets (given dates and pv's)
    Dim T1 As Double, T2 As Double
    T1 = Application.Days360(Sett_d, from_d) / 360
    T2 = Application.Days360(Sett_d, to_d) / 360
    Dim r As Double, d1 As Double, d2 As Double, zwi As Double
    r = underrate
    d1 = (Log(r / Strike) + 0.5 * vola ^ 2 * T1) / (vola * T1 ^ 0.5)
    d2 = d1 - vola * T1 ^ 0.5
    zwi = r * Application.NormSDist(d1) - Strike * Application.NormSDist(d2)
    caplet = inter2(Date_v, PV_v, from_d) * zwi * (to_d - to_d) / 360 * 100
End Function