I got home and put it on the pillow and amazingly the measurement exactly perfect for what I need to cover 2 pillows with the back in different fabric which I already have around. I used one set of the remnant and save the other one for another project.
I just bought a sewing machine from Goodwill Outlet Auction which still perfectly working for $5 what a steal. So, I used the machine to sew the pillow covers in about 10 minutes for both of them.
I really am happy with the result. This is such an easy project and cheap too, consider if you buy new pillows or covers at least you have to spend $15 for 2.