In: Finance
India  | |||
1Y  | 5.69%  | ||
2Y  | 5.78%  | ||
5Y  | 6.29%  | ||
10Y  | 6.60%  | ||
20Y  | 7.03%  | ||
30Y  | 7.06%  | 
Using this data on how to calculate the approximate formula, without the bond prices, we can calculate future discount rates / forward rates in excel
(1+ DR1) (1+ DR2) = (1+YTM2)2
The Discount or Forward Rates can be calculated from the Spot rates using the Expectation hypothesis.
The Forward rate for 1 year prevailing after 1 year 1f1 can be calculated as
1f1= (1+ 2 year spot rate)^2/(1+1 year spot rate) -1
= 1.0578^2/1.0569 -1
=0.0587008 or 5.87%
Similarly
The Forward rate for 3 year prevailing after 2 years 2f3 can be calculated as
2f3= ((1+ 5 year spot rate)^5/(1+2year spot rate)^2)^(1/3) -1
= (1.0629^5/1.0578^2)^(1/3) -1
=0.06631 or 6.63%
In general
The Forward rate for n year prevailing after x years xfn can be calculated as
xfn = ((1+(x+n) year spot rate)^(x+n)/(1+x year spot rate)^x)^(1/n)-1