Syagel is absolutely correct. It is important to have enough extra fabric when you finish off your project for framing or making a pillow, etc. Some stitchers only add two inches on each side. three inches is better -- just in case you get off center somehow.
You can figure out how much fabric you need by dividing the number of stitches by the count of the fabric.
Example: 85 x 61 stitches
85 divided by 16 is 5.31 inches across. Add six inches (three on each side) and you end up with 11.31"
61 divided by 16 is 3.8 inches. Add the six extra inches and you have 9.8"
Round off the numbers and you have the finished dimensions.