How do I determine how much extra fabric is needed to enlarge a quilt?
 

I want to make the quilt pattern, Venice Rose. The largest the pattern with borders is 72 x72. I know that I can enlarge the pattern on a copier and simply chose the enlarged percentage. What I don't know how to do is to determine how much extra fabric do I need to purchase. I've been looking online at a lot of formula's but I can't seem to find the right one. I would really like to get going on this project, it;s going to be for my husband.

Thanks for your help!:)

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I usually measure/calculate square inches in these instances. 1440 square inches (36 x 40) in a yard of fabric. Enlarge on the copier and then calculate how many sq inches/color or fabric.

I have EQ so it is no problem. You need to figure out how many more blocks you will need and figure out how much fabric is used in each block. Also will need to recalculate your borders. Another untried method would be if the original pattern had 20 blocks and you want to make 30 blocks, multiply each yardage by 1.5.
Ex: 1 yard of background fabric: 1 yard x 1.5 = yard & a half of fabric

If you don't have EQ, maybe you have a friend who does and who will gladly help you out.

I have friends who ask me for help and I find it fun to do it with them.

Divide the "new size" by the "old size"

Example:

You want the quilt to be 100 x 100 and the pattern says 72 x 72

(95 x 95) divided by (72 x 72) =

9025 divided by 5184 = 1.741 (round up to 1.75)


Multiply the fabric requirements given by the result to get the new requirements.

Example:

Fabric requirements:

Blue: 1-1/2 yards
Green: 1-1/4 yards

Change to decimals:

Blue: 1.5 x 1.75 = new requirement = 2.625 = 2-5/8
Green: 1.25 x 1.75 = new requirement = 2.1875 = get 2-1/4

If one wants to make the new item larger than the original, the result will be greater than 1.0
If one makes the new item smaller than the original, the result will be less than 1.0

I don't know if this will help, but this is a very cool enlargement chart for blocks.
http://www.thequiltedsnail.com/scale.html

I drew a 7 inch block out in Excel. If I wanted to turn it into a 14" block, the block became 4 times bigger, because it is double as wide and double as long, thereby having to add 3 more 7 inch blocks to it. To me, this means, I would have to buy 4 times as much material as the pattern called for. Not having tried or verified this, I would definitely rely on the quilters here who know what they are doing.

This board makes me think and question what do I really know about quilting? I always learn something new.

(14x14) / (7x7) = 4

In many cases, it is easier for me to get out my calculator out than to get to one of the computer programs.
(Yes, I do know that my calculator IS a computer)

I have always liked math, but don't seem to know how to apply it to quilting. The way you did it is much simpler and quicker than what I did and makes perfect sense. I am glad you posted the equation.

what kind of colors are you going to use for this pattern? Multi colors? shades of thhe same colors? only a few colors? Also how big do you want to make it? IMHO this pattern does not seem to be really easy to enlarge due to all the small pieces. Perhaps you can add more borders to make it the size you want. If not then to determine how much extra fabric you will need- easy -b just add some to the original amount required . EX- if the original amount was 1/2yd then increase it to 1 yd: 1 yd to 1 1/2yd. That should give you plenty of fabric.

to me this looks like a wonderful medalion quilt that needs to be in the center of the bed with borders framing it or borders as the drop.