Note: For a twin bed you’ll need about 1 1/2 yds. off 54” fabric; For a double, queen, or king bed you’ll need about 3 yds. However, actual yardage needed will be determined by pattern or plaid size, repeat, or whether you’re running the fabric lengthwise, called “railroaded.”
2. Decide on the size and shape
First measure the width of your bed and decide how high to make the headboard. Remember that the box spring, mattress, and decorative pillows will cover up part of the headboard, so you may want to add more height to compensate. I recommend having the bottom of the fabric-covered wood headboard start at the top of the box spring Total height of this top section (not counting the legs) will be about 36 inches.
Now you can experiment on newspaper until you’ve arrived at a top shape you like. It can be straight across, a perfect arch, cut at the corners, or serpentine. On a first project like this, the simpler, the better.