giorgio10

I’m assuming that by “N=8.5, I/Y=3, pmt=4, and FV=100” you are trying to caclulate the value of the underlying bond in 18 months.
1) N should equal 17, since in 18 months you have 17 coupon payments left.
2) PYMT should equal 0.04, I/Y should be 0.03 and FV should be 1
2) Even if you do this you will not calculate the no-arbitrage CURRENT price of the futures contract since you are not taking into account the risk free rate.