Pattern Repeat Calculation



Whenever you sew two pieces of patterned fabric together for making clothing, using lace curtains or drapery fabric or whatever, it is necessary to match the pattern across the two or more pieces just the same as you would when wallpapering a room.  This can be accomplished using an easy but wastefully expensive method or by actually using a formula to get exactly the amount you need and not an inch more than is necessary.  These days with fabric as expensive as it is the better way would be the more accurate formula method.  It just takes basic arithmetic and a little more effort on your part.

Before we go into either method we have to know the pattern repeat.  The way to measure the pattern repeat would be to measure from one part of a pattern to exactly where the same part of the pattern repeats itself. We can then use that amount when arriving at the total yardage needed for our project. First you may want to review the Fullness, Hems and Rod Pockets page to figure whether you want a single or double hem. To ascertain the exact length you may want to review how much fabric it takes to how much fabric it takes to add hems to the overall finished length.

Easy Way

If you choose the easy way you would first figure what the exact length of each piece of fabric would be and then add a full pattern repeat to each length.   When sewing the widths together you would line up the pattern on each width and cut off the excess at the top of one piece and the bottom of the other.  That is all there is to it but you will be purchasing more fabric than you need just to end up throwing it away.

Much Better Way

By choosing the far more accurate and less wasteful way you could be saving a lot of money when fabric costs are so high.  To do this you would first establish the pattern repeat as before.  Now comes the challenging part.  You would have to divide the cut length you actually need by the pattern repeat and round up the answer to the next full number and multiply that number by the pattern repeat.  I know you will have to think abut that a bit but let me give you an example and, at the same time, show you that you can save money this way.  To accomplish this we will use an exact curtain length for the example but any other sewing project would use the same formula.  Let us say that you are making a curtain that involves two or more widths of fabric to be sewn together.  Let us also assume that including an amount for the top rod pocket and the bottom hem you decide that you need each width to be a cut length of 100 inches.  If, for instance, you have a 26 inch pattern repeat we will plug that into the formula and see what happens by using the easy way and the better way.

In the easy way we would just add the cut length of 100 inches to the pattern repeat of 26 inches.  Since we are using two widths it would be 126 times 2 divided by 36 inches 126X2/36=7 yards.  When using the more accurate method we would divide 100 by 26.  The answer would be 3.85 which we would round up to 4.  You would then multiply 4 times the pattern repeat which equals 104 inches.  104 inches times 2 widths equals 208 inches divided by 36 inches.  104X2/36=6 yards.  Cut the lengths and place them side to side when the pattern matches. You will then cut off the excess at the top of one piece and the bottom of the other. That will give you exactly what you need but you will have to cut off far less than when using the easy way.

You can easily see the cost savings in this example.  Say your fabric costs $19.95 per yard, which is not all that much in today’s prices.  By buying 6 instead of 7 yards you save $19.95.  If your project is larger you can see the advantage of taking your time and doing it right.  Once you have figured out how much each length will need you then can figure out. You are ready to order fabric and proceed to sewing the finished product.

 We wish you the best of luck in your decorating endeavors

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