Math calculations when downsizing a quilt pattern
#1
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I see a pattern for a quilt measuring 84 x84” that I want to make - it’s 7 blocks by 7 blocks for a total of 49 blocks, each block being 12”x12”
I want to make it smaller - 60”x60”, 5 blocks by 5 blocks for a total of 25 blocks.
I’m not sure how much fabric to buy. Since the # of blocks is almost half of the original should I cut the fabric requirements in half and had a bit? For instance if it calls for 2 yards, buy 1 1/8 or maybe 1 1/4? (Gets a little trickier when it calls for odd amounts like 1 2/3.)
And I know it will get even trickier when it comes to actual cutting and figuring out how many squares to cut and hsq’s to make. I’ll cross that bridge when I come to it.
I want to make it smaller - 60”x60”, 5 blocks by 5 blocks for a total of 25 blocks.
I’m not sure how much fabric to buy. Since the # of blocks is almost half of the original should I cut the fabric requirements in half and had a bit? For instance if it calls for 2 yards, buy 1 1/8 or maybe 1 1/4? (Gets a little trickier when it calls for odd amounts like 1 2/3.)
And I know it will get even trickier when it comes to actual cutting and figuring out how many squares to cut and hsq’s to make. I’ll cross that bridge when I come to it.
#2
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I'm afraid you'll have to do some math. I would break down one block into its components. How many background pieces and what are their sizes, the same for each of the other elements. Once you know how many pieces you need of each fabric and size, you need to multiply by the number of blocks. Then you need to figure out how many pieces you can get from a width of fabric. There are sites that can help you with the last part. This site is pretty good.
https://www.quiltersparadiseesc.com/...Calculator.php
https://www.quiltersparadiseesc.com/...Calculator.php
#3
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There are no good quick answers without knowing what shapes/sizes you want. For your example of half and little more might not give you enough yardage for wide sashing strips, you might be 2" (or whatever) short of what you need to cut even if the overall area of yardage is enough.. For a rough estimate, I would multiply the stated yardage by .75 -- so 2 (yards) x .75 = 1.5 yards. That might leave you with some scrap -- I'm fine with that ![Smile](https://cdn.quiltingboard.com/images/smilies/smile.png)
When I figure out yardage, I use a WoF (width of fabric) as 40". Sure, sometimes you can get in a whole 2" or slightly larger piece over that, but you'd be surprised at how many fabrics are just 40" usable.
Remember that for HST, while normal seam allowance is .25, the ends of triangles is 7/8 -- I use a full inch for figuring yardage. And cutting and sewing too -- then I trim down to the proper size.
As GingerK said, count the number of pieces of each color you will need for a block. You can either write down the measurements or use graph paper --- but you should write down each step and remember your seam allowances!
Calculators either in your hands or on your computer are a great thing! As is basic lined or graph paper. I also keep tape in my sewing kit so I can put together pages if needed (tape on back, it typically doesn't allow writing over). For a twelve inch (finished) block you will definitely need more area than a standard piece of 8.5x11 printer paper.
![Smile](https://cdn.quiltingboard.com/images/smilies/smile.png)
When I figure out yardage, I use a WoF (width of fabric) as 40". Sure, sometimes you can get in a whole 2" or slightly larger piece over that, but you'd be surprised at how many fabrics are just 40" usable.
Remember that for HST, while normal seam allowance is .25, the ends of triangles is 7/8 -- I use a full inch for figuring yardage. And cutting and sewing too -- then I trim down to the proper size.
As GingerK said, count the number of pieces of each color you will need for a block. You can either write down the measurements or use graph paper --- but you should write down each step and remember your seam allowances!
Calculators either in your hands or on your computer are a great thing! As is basic lined or graph paper. I also keep tape in my sewing kit so I can put together pages if needed (tape on back, it typically doesn't allow writing over). For a twelve inch (finished) block you will definitely need more area than a standard piece of 8.5x11 printer paper.
#4
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Can you give us a link to the pattern you are using?
I think one could get by with 60% of the original yardage (assuming there are not long borders, etc) to 2/3 (67%) of the original requirements.
As Icebloom mentioned, if there are a lot of HSTs involved, it is good to have a bit of extra.
I think one could get by with 60% of the original yardage (assuming there are not long borders, etc) to 2/3 (67%) of the original requirements.
As Icebloom mentioned, if there are a lot of HSTs involved, it is good to have a bit of extra.
#5
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I always buy more fabric than the pattern calls for. I'd rather have left over to add to my stash than run out and have to madly try to find more to complete the project. If it calls for 2 yards. I'd buy at least 1 1/2.
#7
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Thank you for your answers! I haven't purchased the pattern yet so I can't figure out by counting the # of pieces needed for each block. Here's a link to the pattern.
https://www.frenchgeneral.com/produc...ips-march-2023
https://www.frenchgeneral.com/produc...ips-march-2023
#8
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That's a pretty cool pattern. At first I thought it was alternating blocks -- which it is, but it is the same block in two different color ways. The center large print is the same in each block. I don't see any big areas of concern that I had before seeing the pattern. I think though the instructions would really help you and suggest you buy the pattern.
Once you have the instructions, multiply each amount by .6 or .75. With .6, round up to the nearest fabric cut. For example, two yards would be 2 *.6 = 1.2, round up to 1.25 yards. 3 yards * .6 = 1.98, so 2 yards. If you use .75 then 2 *.75 = 1.5 yards, which would give you a little extra breathing room. Likewise, 3 * .75 = 2.25. If there are pieces under half a yard you might as well just buy as halves or whatever is listed. (Having worked at a fabric store at one point of my life, I personally don't buy anything under half a yard...)
Once you have the instructions, multiply each amount by .6 or .75. With .6, round up to the nearest fabric cut. For example, two yards would be 2 *.6 = 1.2, round up to 1.25 yards. 3 yards * .6 = 1.98, so 2 yards. If you use .75 then 2 *.75 = 1.5 yards, which would give you a little extra breathing room. Likewise, 3 * .75 = 2.25. If there are pieces under half a yard you might as well just buy as halves or whatever is listed. (Having worked at a fabric store at one point of my life, I personally don't buy anything under half a yard...)
#9
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Ready for more math or math explanation?
To figure out the percentage which you already knew was "about half" the mathematical approach is to divide the number of blocks you want as opposed to the number of blocks designed -- 25 by 49 or 25/49 which gives us 0.510, so we know that .6 will work for the reduction without as much extra as my .75.
All you have to do is multiply the yardage requirements by .6 -- is easy with whole yards (like I used 2 and 3) above. Quarter yards are .25, .5 or .75. Thirds in decimal equivalents are .33 (1/3) and .66 (2/3). In your it gets harder example, 1-2/3 yards equal 1.66, 1.66*.6 = 0.996, or round up to 1 yard![Smile](https://cdn.quiltingboard.com/images/smilies/smile.png)
Since the design is actually flat set 12" blocks and you want it to be 5x5 blocks that makes the design work out nicely. Look at the upper left corner to see the block -- it ends with dark corners. We'll call that Block A. Block B next to it has white corners. You will need 13 Block A and 12 Block B.
Isn't it amazing how color values change the design?? I mentioned in the post above that the center large prints are the same in both blocks (maybe even fussy cut a bit) -- the star points are also the same color in both blocks. But for me, they pretty much disappear in Block A but come back strong in Block B when set against dark fabric.
I hope you will post pictures of your project!
To figure out the percentage which you already knew was "about half" the mathematical approach is to divide the number of blocks you want as opposed to the number of blocks designed -- 25 by 49 or 25/49 which gives us 0.510, so we know that .6 will work for the reduction without as much extra as my .75.
All you have to do is multiply the yardage requirements by .6 -- is easy with whole yards (like I used 2 and 3) above. Quarter yards are .25, .5 or .75. Thirds in decimal equivalents are .33 (1/3) and .66 (2/3). In your it gets harder example, 1-2/3 yards equal 1.66, 1.66*.6 = 0.996, or round up to 1 yard
![Smile](https://cdn.quiltingboard.com/images/smilies/smile.png)
Since the design is actually flat set 12" blocks and you want it to be 5x5 blocks that makes the design work out nicely. Look at the upper left corner to see the block -- it ends with dark corners. We'll call that Block A. Block B next to it has white corners. You will need 13 Block A and 12 Block B.
Isn't it amazing how color values change the design?? I mentioned in the post above that the center large prints are the same in both blocks (maybe even fussy cut a bit) -- the star points are also the same color in both blocks. But for me, they pretty much disappear in Block A but come back strong in Block B when set against dark fabric.
I hope you will post pictures of your project!
#10