Free Fabric Calculator
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Fabric Calculator

The stitch count column on the left side of the chart is the number of stitches in your pattern. So, for example, if you are working on 14 count:
 

75 stitches wide = 5.36 inches wide
45 stitches high = 3.21 inches high
5.36W x 3.21H

Remember, if you are using linen (over 2) you should calculate at 1/2  the linen thread count. For 28 count linen, you would calculate for 14 count because you are stitching "over 2".