Doubts regarding Risk free Rate calculation in option calcuator?

[rebeck10]

BSCall(s, x, r, sigma, t) computes the call price from the
stock price (s), the exercise price (x), the risk free rate (r), the
volatility (sigma) and the time to maturity (t).
what is r value for today on nseindia.com
to compute for tommorw?

 

[rebeck10]

anyone , knows the default value atleast to be provided ?? plz reply asap

 

[register1803]

did not understand what you are talking about please be more descriptive

 

[rebeck10]

i have got a function in excel to calculate option price ,using black schole model.
In that one of the parameters is Risk free rate of interest r
So what value should i substitute for that for daily calculation?