Things You'll Need:
- Tape Measure
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Step 1
Measure the window length for the valance length. Position a tape measure from the top of the window frame to the crossbar. Divide this number by 2 and add 5 inches for a hem allowance. For example, if a window measures 36 inches, divide 36 by 2 to arrive at 18, but adding 5 to 18, yields 23. So you would need 23 inches of fabric to make the valance for a set of bistro curtains.
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Step 2
Determine the finished valance width by measuring from just inside the frame on one side of the window to the same spot on the other side. Multiply this figure by 2.
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Step 3
Calculate the length of the tier. Measure the window from the top of the sash to the bottom of the frame then add 5 inches to the figure.
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Step 4
Find the width of the tier by measuring the width of the window. Each tier equals the width of the window. Most windows require at least 2 tiers.














