Thursday, December 10, 2009

how to calculate quilt measurements


Math is a huge part of quilting, like it or not. I'm not particularly fond of math, but it's a necessity, especially since I rarely use a pattern.

I get emails all the time asking questions like:

"I'd like to make a twin size quilt out of charm packs. How many squares do I need?"

Or, "How many more blocks will I need to make the 9 patch quilt into a full size?"

Or, "I'd like to make your stacked coins quilt, but in a queen size. How many more charm packs and how much yardage would I need?"

These are just a few that come to mind. Well, today I'm going to walk you through these and show YOU how to do the math. :) Some of this may be pretty basic, but I think it's worth covering. I work with a calculator and a piece of paper and a pencil. No EQ for me. I'm old fashioned that way.

First off, I'd like to list some basic quilt sizes:
A nice baby size quilt is around 42" x 52".
For a square baby quilt, anywhere from 36" to 42" works well.
A crib quilt measures 45" x 60".
A nice lap size quilt is 60" x 72".
Twin size, 63" x 88".
Full size, 78" x 88".
Queen, 84" x 92"
King, 100" x 92".

If you are making a quilt for a specific bed in your house, it's best to measure the top of your mattress and add the amount of overhang you want on each side, then you will have the perfect measurements for your bed. I'd recommend this, especially if you have a very deep mattress, or if you have head and foot boards to deal with. Or bunk beds.

These are target sizes. If your block calculations don't work out quite right, just round up.

Ok, for the the first question, how many charms will I need to make a twin size quilt?

A charm square=5".
Take away 1/2" (for seam allowances) and your finished square will equal 4.5".
63" (width of quilt) divided by 4.5" (finished square)=14
88" (length of quilt) divided by 4.5" (finished square)=19.56, which would round up to 20.

So 14 x 20=280 charm squares. Your layout will be 14 blocks wide by 20 blocks long. The quilt will measure 63" x 90".

Not too bad, right?

For the 9 patch quilt:

The finished quilt measures 66" x 90" for the twin size. Each 9 patch block finishes at 6" and each sashing strip finishes at 2".

Since you want the quilt to be at least 78" wide, you will need 12 extra inches. You would need 20 extra blocks (ten for each additional column) and then add in the sashing 2" finished x 2 strips. The width of the twin quilt is 66" +12" (for the two extra columns of 9 patches) + 4" (for the two extra strips of sashing) =82", which is a bit wider than your target of 78", but close enough. Plus, it's nice to have it a bit too large than a bit too small. So the number of 9 patches needed would be 70 (from the original pattern) +20 = 90 for a full size quilt. Does that make sense?

Now, for the toughest one...a queen sized stacked coins quilt using this tutorial.

Your target size is 84" x 92".
Coins are cut 2.5" x 5", which will finish at 2" x 4.5".
The sashing is cut at 3.5", which will finish at 3".

For the width of the quilt:
11 columns of coins x 4.5" (finished width)=49.5"
12 columns of sashing x 3" (finished width)=36".
49.5" (total coin width) + 36" (total sashing width)=85.5" wide. Perfect.

Now, for the length of the quilt...

This one will be worked backwards. You want it to be 92" long. Subtract 6", for the top and bottom sashing, which will give you 86".
86" divided by 2" (finished height of each coin) =43.
So 43 coins in each column x 11 columns= 473 coins.

473 divided by 2 (number of coins that are cut from a charm pack)=236.5, which would be rounded up to 237 charm squares required.
If there are 40 charms in a pack, you would need 6 packs of charms.

For the yardage needed for sashing, you will need 12 strips that are cut 3.5" x 86" and 2 strips that are cut 3.5" x 85.5". For this step, I'd enter those numbers into the handy dandy quilt calculator (someone had directed to me awhile back, thanks to whomever did so, it's so very wonderful!) which will tell me that:
for the 12 strips that measure 3.5" x 86"= 2.5 yards
for the 2 strips that measure 3.5" x 85.5"=2.375 yards
for a total of 4.88 yards, to which I would just round up to 5 yards.

Ok, any questions on how to do this? Remember to calculate with your FINISHED block size, not your CUT size, or you will have a quilt that will be much smaller than anticipated.


After all this, I feel compelled to ask, (like blogger does at the bottom of their help pages) was this article helpful to you? ;)

120 comments:

Brittany said...

Wow, this post was amazing. Thanks so much!

Cheri C. said...

YES! I am new to quilting and I don't like to ask a lot of questions to quilters. I know quilters are helpful people but I get embarrassed OR I would bombard them with too many question. So, I love getting information on blogs as detailed as this. Thank you!!!

Bonnie in Iowa said...

Thanks so much. I am fairly new to quilting and joined a group that had been together for a long time. Everytime I ask a question I get told "you should know that; we've talked about it". Only problem is that it was discussed long before I joined. This was so helpful.

Nichole said...

Nice explanation. This one of my favorite parts of quilting. I'm a nerdy math type who loves to draw things out on the grid paper. :)

claudia said...

YES!!! Thanks for the tutorial! A big help!

Lise said...

Yes! I was totally annoyed recently, searching for the (simple, I thought) answer to the question "how big should a twin quilt be?") I'm writing down your answers in my journal for future reference.

Lise said...

Yes! I was totally annoyed recently, searching for the (simple, I thought) answer to the question "how big should a twin quilt be?") I'm writing down your answers in my journal for future reference.

Lee said...

This helps more than you know. I don't like math, but keep telling my kids learn it well you will need all your life. Think I will print your notes and keep in my reference binder. thanks for taking the time to write it all out for us.

pigbook1 said...

I starred it in google reader so it must be helpful! :-)

Shea said...

Yes!
The math doesn't typically give me problems. I hope not, since I *teach* math for a living!

However, that online quilt calculator you linked to is AWESOME!!

DeeRoo said...

Thanks AJ...I am going to FAV this post. Since I really just started quilting in June I have only used fabric I already had or remnants from the store. I have never bought a charm pack or jelly roll, etc., I just actually learned what everyone ment by those terms!:) So now I'll be able to purchase some of those items with a bit of knowledge!:)

RosaMaría said...

you are the best! i'm a little lazy with the calculations... but your post its a good example about the easy way with math... thanks!

Jessa said...

I just found your blog a few days ago. It is awesome! Thanks so much for all the great and inspiring info! In answer to your question, this particular post wasn't a huge help to me just b/c I like doing the math :) but I am going to write down the target bed sizes - that's great info to have!

I have been spending lots of time going through your tutorials and other posts - what a wealth of great information! Such fun! Thanks so much for putting this together!

RosaMaría said...

you are the best! i'm a little lazy with the calculations... but your post its a good example about the easy way with math... thanks!

Ginger said...

Great post! Thank you! I just have one question: At the end, for the coin quilt, you are essentially purchasing an extra 2.5 yards of sashing fabric in order to cut two 3.5" strips from it, right? So if you were willing to piece the sashing strips at top and bottom, you would be able to do this with much less "waste" (Not that buying fabric is ever a waste, but my wallet would appreciate it.)

Libby said...

WOW!!! How generous of you!! I used to work in a quilt shop and we got those questions all the time! It felt good to pull out some scrap paper, pencil and calculator and show the customer how to figure out the yardage, strips, length,etc for themselves!
Libby

Needled Mom said...

Perfectly clear. Thanks for all the info.

amandajean said...

Ginger,

You are absolutely correct. Although having extra is helpful for those pesky cutting errors. ;)

aj

Nix said...

Genial...!!! I'm a begginer too. And the final size of the quilt is one of the bigest concerns for me. Thanks for posting!!

Cheryl Arkison said...

Helpful for me to see that I'm not the only one who uses pen and paper. I often sketch the rows and columns too, for a visual reference.

Jessica said...

Thanks for helping clear the boggling math/quilt situation!!

Alissa said...

Wow! You are so great for putting together this post. Math is the part of quilting that people never talk about and it's key. As much as you try and avoid it, there's SOME math that always has to happen! Wonderful post.

Neverwas said...

Thanks for such an informative post! I've been trying to calculate my quilt measurements rather than just winging it and this helps so much.

Juliejaz said...

That is very helpful, thanks for explaining that.

Mary said...

I use EQ most of the time but also use a calculator when needed. Quilt math is easier than regular math :)

The question I get all the time is about fabric yardages although I state very clearly that I don't provide them with my instructions sheets since most of my quilts are made from scraps so I don't bother to calculate yardage even for myself.

Beverly said...

Wow. I hate math. Thanks for doing it for me! Now if my husband has any questions the next time I figure out a quilt, I can have him read this! (He's my quilt-a-matician) ;)

VeeV said...

Amandajean!!!
lovely post....as always..

i have now found a 'new' term... and want to know what "EQ" means??

I'm thinking it's probably very simple...but...

xo
eva

Jennifer said...

Fantastic! I was calculating what size I needed to cut some squares recently to make some pinwheel blocks and my husband looked at my calculations and asked what I was doing. I said "quilt math" to which he replied (and I can say this here because most of us are women) "Is that like period math?" Sorry ladies, he's taken.

Valerie said...

I hate math, but I love your quilt math :) Thanks!

Anonymous said...

AJ, You are so kind to help us all out with this valuable information. Thanks so much. Mary Jo

Amy Renee said...

Really helpful, thanks! My method has gotten me to where I need to go but it takes a long, long time.

Skooks said...

This will be so helpful in the future! I am just finishing up my first quilt ever from a pattern (so I knew how much to buy). Going forward I'd like to try some different stuff on my own and this will definitely come in handy.

Thanks!

Linda said...

Pretty much the same way I do it. LOL. I use some graph paper, graph out what I want to do and then start in with the math. :)

Lauren H said...

Yes, thank you! I have a couple of quilts that I want to make, but don't have a pattern or have one for scraps but not amount of yardage needed. Your post today has inspired me to sit down with paper, pencil and calculator and . . . "just do it!"

Sara said...

Oh, yes...very, very helpful! Thank you for taking the time to do that...

Mama Pea Quilts said...

Was this article helpful? YES! Extremely! It would have taken me about four eight hour days to figure all that out and get it written up in the very understandable form that you did. Thanks for going to the trouble.

MamaBagel said...

YES! I even printed out your basic quilt sizes to share with my quilting group (along with your blog address on the bottom). Thanks so much!

karen said...

Wow, this is so helpful as I just started to quilt. And this was my first long copy and paste and I did it!!! Thanks for making my day.

Nicole said...

Holy math skills Batman!
Great informative post, I have seen bits and pieces before in books etc. but appreciate it being in one place.
Thanks!

Lois Grebowski said...

I'm a newbie and this post is chock full of info goodies... thanks!

Mama Urchin said...

Another reason to make the quilt a little big is the shrinkage caused by quilting.

twrightgirl said...

this was totally helpful. i am a novice to the novice when it comes to quilt making and i am behind 2 quilts for my 2 youngest girls. thank you thank you thank you!

Kristen said...

Amandajean: This post was very helpful to me!!!! I am a total newbie and I adore your blog. I especially love your money-saving tips with the IKEA sheets, etc. You rock!

Purple Paisley Patch said...

Thank you sooooo much, this is extremely helpful. I wish I had some ink in my printer so I could print it out for easy reference. I was good at math at school, but have made so many sewing mistakes due to inaccurate math.
Thanks for taking the time to explain all this, you are a very generous soul.
Merry Christmas to you and yours.
Kelly :-)

Lina said...

Very helpful. In my extremely limited quilting experience this is how I do it too. Sometimes a bit of graph paper too, just to be sure!

Elle said...

Thank you once again! One of the things that I like best about quilting and sewing is the math so I had fun reading your post.
PS if you ever teach a class in New England I'd love to know!!!!

Shanley said...

I just posted this week that I use Excel for my quilt math. Typically when I want to use all of a fabric that I love.

Di~ said...

:) I love it!!! You the woman!
I bet you didn't have anything else to work on this lovely December day, did you???:)

One Flew Over said...

You are an absolute gem! I cannot tell you how bad my math is and this post will help me out... A LOT!

Thanks xx

Denise said...

Super helpful. I'm bookmarking this entry right now.

Kristin said...

Very helpful! Thanks so much for this and all your fabulous tutorials. I love coming here for my daily dose of sewing inspiration....

Collette said...

Yes, it was very helpful, despite the fact that my eyes crossed a couple of times. ;-) I'm bookmarking it now though.

Kim said...

Yes, this was very helpful. I'm copying it right now since I hate doing math!

BreAn said...

Yes! Huge help. This way I don't need to go find a quilter to ask these questions. I can do it myself. :)
Will be saving this info for sure!

Susan K said...

That was so helpfull - thanks

c'est Moi! the tink-n-frog said...

I'm new to quilting. I, like some of the other posters, would like to thank you for taking the time to do provide this info.

Suzanne said...

Are you familiar with the expression, "Give a man a fish and he'll eat for a day. Teach a man to fish and he'll eat for a lifetime"?

There are a whole lot of new fishers out there because of this post. Thanks so much!

Rose said...

Oh man, I would never want to do a full size stacked coins quilt! I did a table runner, and did each strip the same, and yet when I added my sashing, the strips slowly got longer from one end to the other, so my rectangular table runner was almost triangular. Hated it, didn't want to rip it all out so I squared it up, cut off and wasted a bunch, and finished it. I can still tell it's wonky, and it makes me so mad!! I don't know where I went awry, if it was piecing the strips or adding the sashing, but I sure hated it, and will never to another one!!!

Antique Rose Designs said...

Amandajean thanks for taking the time to post this info. I always get nervous when calculating the measurements for a quilt. I check and double check and triple check before cutting the fabrics incase I stuff. This info has been very very helpful. I'm going to print it and pin it to my wall for future reference. Looking forward to seeing your next quilt. Carol

momawake said...

Funny you should post this today. I'm always asking my dh to help me with the math for how much yardage I need to buy in order to have the right amount for say borders. The basic formula is finding the area or base x height then dividing that by 1296 which is how many square inches in a yard. That'll give me one border so then I multiply it by two. Then do it again for the other two border pieces. Add it all up for the yardage.

bruinbr said...

YES! Thank you for posting this! :)

Metanoia said...

My 2 cents is: I do mine visually. I create a photoshop document substituting cm for inches (ie for a cot size I'd do a 50x60 cm document for a 50"x60" quilt design) then I turn on 1cm grid lines... then I go to town until I'm happy... then I work out how much of each fabric from there. A little less maths and helpful while I'm sewing. ;)

Janet said...

I do it the same way, pencil, paper and calculator because the brain's not too good on math either. This was a lot of work so thank you, I'll print it out.

why not sew? said...

Thanks for all the great info and for the link to the quilt calculator. That looks so neat. I use a pencil, calculator and graph paper. I make a rough drawing and then measure, and measure and remeasure.LOL!

Anonymous said...

This post is fantastic, even if here In France we use centimetres
I think I can just transform
I am really a fan of your blog, you made me love again quilting

Cath06

Julie said...

Thank you! This is exactly what I needed... but was always too afraid to ask :)

Brenda said...

Oh my gosh! This is wonderful! Thank you!!!!!

The Calico Cat said...

Hey, I see my question! Thanks again & thanks for the math lesson.

I'd be 4 steps ahead if I could just remember seam allowances!

pdudgeon said...

i'm thrilled to see all the new quilters out there who will really benefit from this information!

Quilt on, ladies!

ale balanzario said...

Thanks so much for this post, it will be very handy :)

Lynn said...

I'm printing this out and keeping it handy. Although not necessarily a new quilter I am a mathematically challanged one!

Kelly O. said...

oh yes! thank you!

Jessica Christensen said...

This was great, Amanda Jean. It's what I do, but I've been asked a lot of questions about the math portion of quilting, and now I will just refer them to you. = ) You are awesome. I can't remember who said you were the Google of quilting blogs, but I would have to agree.

DIDI said...

Well of course this post is useful! I only wish I hadn't already spent a long time figuring it out by myself, it would have taken me far less time to read it from your excellent explanation! Thanks !

Cara said...

I too am not horribly fond of math, and to be honest EQ can be misleading so often I get out the paper and pencil, and use the calaculator on my computer or blackberry. That is very helpful for a lot of poeple thanks.

Heidi said...

What a great post! I will have to reference it over in my quilting bees, so the members have something to help them calculate yardage. You rock!

BTW, we should point Bonnie from Iowa over to some of the quilting Flickr groups that are so helpful with answering questions (http://www.flickr.com/groups/oldredbarncoquiltalong2009/).

JenniferO said...

Wow, I'm sure someday this will be VERY helpful. Today it's just giving me a math headache.

Aimee said...

Thanks Amanda! Very helpful information.

Tiziana said...

tutto ciò che conosco lo devo a te e non smetterò mai di imparare da te...quindi grazie
per tutto e tutti i tuoi tutorial

PunkiePie said...

Most helpful indeed!

Sonja Hoyle said...

Wow! So informative! Thanks for sharing! I always seem to fuddle through my quilts, measuring twice, cutting once. And I always buy too much fabric (just to be on the safe-side). I love quilt math, but then again, I love any math, especially geometry! With your tips and pointers, perhaps I will now buy exactly what I need, rather than my guesstimation technique! LOL Thanks again!

beth said...

well, you did it again. You took us to place no one dares to go: Math class. And look at all the happy people! Who would have guessed? ME: I "wing it" almost everytime I make a quilt and hardly ever know what size I'm going to end up with. You're such a good role model. :)

Anonymous said...

Thank you for the wonderful post...it answers so many questions :o)

Lori in South Dakota said...

ROFL--you just gave a tutorial to a very mathimatically challenged person. I usually just call my friend Henrietta--who is a math whiz!

Mommy of two little blessings said...

Don't normally leave a comment on your spot here as you always have SEVERAL, but I greatly enjoy seeing what you are doing quilt wise. If you get the chance to stop by my blog/journal, you will see I am a momma to two young blessings and enjoy learning new things in the home, I have a good relationship with my sewing machine. My math is HORRIFIC! So I read this entry carefully even trying to do the math for a quilt top I have in the making. It's one for our son and has my second time around with embroidery. So I got out my paper and did the math. I hope I did it right, now to double check it with my engineering husband. Poor guy is married to a creative person. *wink* He is my "calculator". *smile* I am working on my math and getting our children involved in math in the kitchen with recipies even though they are 4 & 2. *smile* It's never too earily to get to using your math. *big smile* Thank you for this entry and for breaking things down step by step. Sincerely, Mommy of two little blessings

Chicago Sarah said...

Very helpful! Thanks for putting all the sizes in one place!

Dallas Designing-Diva said...

You rock girl! Thanks so much for sharing & breaking it down!!

heather said...

You are toooooooo kind to leave tell everyone this. I guess since I learned from you I just learned to watch you and then figure them out myself! I guess it beats answering a million questions. Tooooooo kind I tell you! :)

Keri said...

Thanks so much for posting this. I am CONSTANTLY messing up with that part of my quilt. You would think I would learn! I'm sure this will help with the next one.

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jen said...

I've known how to do the math aspect, but what I wasn't aware of were the measurements for each size quilt; so thank you very much!!!

Renee said...

A great and very helpful post ~ Thanks!!!

Laney said...

Thank you! This is very helpful information.

Katherine said...

What a sweetie you are! Thank you, Amandajean.

Like you, I know the math is necessary but find this is the part that least thrills me. I just always want to get on with the sewing! (but I do know how important it is to get the math right first! ;o)

Anonymous said...

nice blog..................................................

Kelli said...

very helpful. I put this info to work for me this morning. Now back to quilting. Thank you.

Spendlove said...

Very helpful - thanks so much for a behind the scenes figuring - haa, haa, your blog is delightful - thanks for all the kind words of advice and direction you share

Lenna Green of Stitching Cow said...

Wonderful content, you are a gem for sharing this with everyone. I agree like it or not quilt making involves the maths!!!!

Rebekah said...

I calculate things the same way, too! It brings out my inner math geek and I love it :)

Leini said...

I've found that the following program can be quite useful:

My Quilting Math Buddy

susan said...

Wow, this is why your quilts always look so good- you actually plan them! I tend to make mine up as I go along, which leads to much angst over not having enough of particular fabrics once I get rolling. I never work to a particular end size- I just add borders until I get sick of wrestling them under the machine. I do admire your stacked coin quilts- I may just use your mathematical genius to make one! Love your blog. Susan

jaybird said...

very well written.. i happen to love the math part of quilting.. it is one of my favorite things! ;-) {i'm not kidding}

happy zombie said...

So what you're saying is, is that when I get questions asked of me... I just refer them to this post? I love the math part... just not explaining it. Echo'd voices of teachers past haunt me... "show your work, show your work".

BundleBaby.etsy.com said...

Your information is so helpful to me..thank you! I am getting ready to start my very first quilt, the nine patch and I really appreciate all the in depth info that you give on your blog. :)

Carolyn said...

thank you so much for this. even though it's basic math it really helps that you've layed it out in plain English!!!!!

Anonymous said...

you rock!
thanks for all the facts and nerdy numbers. my cup of tea!
i am so saving this info! :)
anna

Anonymous said...

As I only began quilting over a year ago, I really appreciate when more experienced quilters share helpful info. like you have done. I enjoy photos of quilts, but when I learn something about quilting, it is even better.

Li de Liége said...

Ainda costuro os meus!!!!
liége

mazie marie said...

This answered my question exactly. In addition, the page is bookmarked for future reference. Thank you so much!!

Alia said...

Amanda Jean, I don't get it!???

I am trying to figure out how to make a charm lap quilt using the 5"charm squares and my math aint measurin up!

Any help??

Thanks

cathy said...

THANK YOU! for this post. I have been wanting to make quilts for my kids but had no idea how to measure and as much as I've looked I had yet to find anyone explain it as well as you do! Now they may get those quilts that they keep asking about. Now here's a teaser for you..about how many charm squares can you get out of a yard of fabric? :)

CK said...

Thank you for this! I've just finished pieceing coin quilts for my two youngest girls using the info here and your tutorial on the Moda bakeshop, these are my first attempts at bed size quilts and you explaining the maths made it so much easier :) On to the quiting!

Rachel said...

Seriously awesome (yes, I know I am posting a comment on a post from 2009...lol...but the "new" me has vowed to be more vocal in my appreciation...so, here you have it...LOL) I love this tutorial/lesson. Thank you!

Linda said...

Thank you! This is invaluable info!

Faith said...

Yes, thank you, it's very helpful. I never seem to see any king size measurements. Now I can figure them out for myself.

Sew Loquacious Angela said...

Hi! I think I get it. I'm wanting to make a 36" X 36" table topper...if I apply your calculations to this I get a total of 64 charms. Also, my layout will be 8 blocks wide and 8 blocks long. Is this correct? It seems like a lot?? I'm awful with math, but I've just acquired the quilting bug! Please help if you can.
Thanks,
Angela

leanne said...

seriously helpful information - thanks sooo much :)

Deborah Mitchell said...

Thank you for this tutorial. I could have used this yesterday when trying to figure out how much fabric I needed for backing material. The lady at JoAnn's cutting table was very helpful. Will wait for my next 40% off coupon to by the backing.

Sewalot said...

Not only are you a great quilter--you are a great teacher!

Brooke said...

This is very helpful and very much appreciated.