OK.. I got a few requests last night on calculating fabric for a D9P (Disappearing 9 patch), and let me tell you I have a new admiration for those who teach math!! I also preface this by letting you know that Algebra is the one subject I got VERY poor grades in .. got the answers right.. but couldn't show my work. So here goes...
This is how I calculated my queen/king sized top for my nephew (I'll show a pic at the end). I wanted simple numbers so I went with simple lowest common denominator. I made the squares for the 9 patch 5" each.. that is including seam allowance. For this Tute we are going to use Colors A, B, and C..
color A will be the 4 outside CORNERS of the beginning 9 patch block.. Color B will be the center 4 outside squares in the 9 patch.. color C will be the center square of the 9 patch.

Love the fishy fabric. Guess you are writing more instructions as we type.

A is the fishie fabric
B is the Green fabric
C is the Yellow fabric.

#1 for each block we are going to need 4 fishies... 4 greens .. and 1 yellow.
#2.. this quilt is going to be queen/king sized.. so we're going to make it 6 blocks across and 7 blocks long.. that's 42 blocks total.
#3... for Color A we will need 168 of the 5" squares.. you get that by taking the 4 squares/block and multiplying by the number of blocks.
With me so far?? :thumbup:
Now comes the fun.
Figuring we're using 45" fabric we're going to be conservative and say we can get 40" (across) of usable fabric after taking off the selvages. Soo that means we can get 8 of the 5" squares across the fabric..
Now you take that 8 and divide it into the number of total squares you need of fabric A.. (168).. and that will give you 21.. that means you're going to need 21 rows of 5" squares. so if we multiply 21 x 5.. you will need 105" of fabric.. to cut out the squares for fabric A... and guess what.. you need the same for fabric B!!.. thank heavens finally something easy..lol...
Now for yardage we're going to divide 36" into our 105" needed and come up with 2 yards and 33 inches. Or as we all know 3 yards 'cause we're all about rounding up.
For Fabric C you need one square for each block.
That is 42 squares.. at 8 squares per row. we're going to take the 8 into 42 and get 5.2.. so since we're not into "fragments" of squares we're going to figure 6 rows. That is 6 x 5 or 30 inches of fabric.. so I would round up and spring for a yard of fabric. again giving myself some wiggle room for getting fabric straightened on the grain and allowing for poor cutting.. theirs and mine.
So far we've calculated that for a queen/king sized top we're going to need
Color A=3 yards
Color B=3 yards
color C =1 yard
Wasn't that easy????

OK.. now I know that many of you want borders and are saying.. yah... but I want borders..... Here is where my "creative" math comes in.. and I frequently rely on little diagrams for my own use.
OK.. for the 5" border request I had .. here goes. I like my borders cut from the lengthwise grain of the fabric when I can. For purposes of this tute.. we're going with that.
Going back to our original assumption of 40" of "working" fabric across we're going to need 4 strips of whichever fabric you want for your border.. We are going to say we're using color B for the border..so the total length of the quilt is going to be ... at the most... and that's the best way to figure.. better to have a little left over than not quite enough... 13.5" (size of finished block after cutting, spinning and re-stitching) times 7 blocks long.. or 94.5" PLUS.. 9.5" (borders less 1/4" seam allowance on each) or 104"
This is where I take a couple of shortcuts.. and I have to tell you .. I don't mind having a little fabric left over.. you still have to bind this quilt.. and can use the leftovers in a pieced back.
We know for a fact our longest border needs to be 104"
You need that off the side of the "usable yardage".. so that 4 of those 5" border strips are going to reduce our usable width from 40" to 20"..
out of 104" x 20" usable piece of fabric we can get 84 squares.. I got that by figuring how many rows (5" squares into 104" piece of fabric equals 21 (ok so it has to be 105" long)... then take that times 4 squares across which is 5" square into 20" width of usable fabric. multiply the number of rows we have by the number of squares across and voila.. you have 84 squares. OK so far?
Now we know that we still need 168 squares of this fabric.. so just take 84 from 168 and we need 84 more squares.. Back to method #1.. we can get 8 squares across the full 40" so we divide 8 into 84 and get 10.5 and once again rounding that up.. we need 11 rows of squares.. since we don't want to piece them.. so 11 x 5" will be an additional 55" of fabric.
Adding the 2 yardages needed we find that we need a total of 160" of color B or 160 divided by 36.. you would need 4 yards and 16 inches of that color.. might as well say 4.5 yards..
To summarize you need
Color A: 3 yards
Color B: 4.5 yards
Color C: 1 yard.
I hope this is understandable.. as I said.. I make no pretense of being a Math person.. but it works for me.
Other border sizes can be calculated in a similar fashion. If you need individual help just give me a shout.. this pattern is pretty easy to figure.. I'm not sure I'd be as comfortable to calculate for more complicated patterns for anyone else.

Thank you so much for the tute for D9P. I have a hard time figuring out the math to make larger quilts. It seems as if even my G-Kids all have huge beds. lol Agan thanks for taking the time to help your quilting sisters and brothers on this board. :thumbup: :thumbup: Pam

THANK YOU, thank you, thank you!

Thank you. I just wish your tute had been here last year.... LOL..... when I was doing those 3 disappearing nine patch quilts. Making the quilts wasn't near so bad as doing the math! What a headache!!! Wound up having to buy a different fabric for the borders.....miscalculated on the amounts.

Thank you for the info!

Thank you Tippy! You are the greatest! I sure enjoy our live chats and you are so knowledgeable!

Thanks for the tutorial!!! :)

Need help on how to quilt a D9P, please. I'm ending up with 6" spaces and usually figure there shouldn't be more than 4". I've considered using buttons or yo-yos in those big blocks but that's a lot of buttons/yo-yos! Maybe tie in the middle of each one?

ohh! I LIKE!

Thank you so much for the calculations...makes it much easier to plan...beauty quilts by the way..still love that fishy fabric LOL

Thanks so much for the tutorial. The D9P is definitely one I want to make, and this will definitely help!

for those of you who don't want to bother with math, and who, by mistake, made a 9 patch too small for the intended purpose, here's an option...sew a coordinating fabric strip to TWO sides of your finished 9 patch, then cut both ways as before and rearrange. The extra strip gives more interesting options in placement...and you don't waste that orphan block. Once you try one, it might become interesting enough to make into a whole quilt. You can either be precise and measure the difference between what you have any what you want, calculate seam allowances then cut and sew the strips on...or do what I did and cut extra strip wide enough to accommodate what I would need and sized the block up after I'd finished the new block.

thank you for that. Penny

You may want to consider purchasing a Quilter'sFabriCalc.
by Calculated Industries. I was given one as a gift and I love it. They have come down in price to less that $20 when they are one sale.

THIS IS A KEEPER. Great help on the math. THANKS !!!

I am currently doing the D9P. It is facinating and turning out really well. I am doing 2 queen size for our bedroom (twin beds) and I intend for them to almost reach the floor so I do not have to have dust ruffles. Thank you so much for the opportunity to register and comment.
This is a hugh project, but in the words of my father, "Nothing lasts forever"
janb, Colorado

Wish I had know the calculator was on sale, I bought one for $50! Havent used it yet, but I am looking forward to the next project so I can put it to use.
janb

Hi Tippy I'm new to all of this stuff on-line,but had to comment on this quilt; LOVE -IT !!Judy

Thanks Tippy for creating this tutorial for us, glad we discussed the D9P in live chat!

Thank you.

yes tippy good for you as we say live more learn more thanks

thanks for the informtion on how to calculate the yardage for the disappearing 9 patch

Just joined this forum last night...my eyes are blurry!!! realllly blurry!! I'm good with calculations, but I never heard of a D9P. Where can I see the instructions?

http://www.quiltingboard.com/t-40144-1.htm Here you go.. hope this helps.
AKA the Disappearing 9 patch.

ok, Tippy, appreciate your direction!!

Had some more questions about where to find this so here it is y'all.

Thank you so much!

Thanks for the tute