I’ve always had trouble with numbers. I stand in awe of those of you who can manipulate them with skill and finesse. I break into a sweat if I need to figure out what numbers to punch into the copy machine in order to enlarge a 12″ appliqué pattern into 15″. Are you with me here? Do you have a math phobia too? If you don’t and number among the math adept, please feel free to smirk and feel superior. I envy you.
Quilting has a way of sneaking past phobias. Thanks to a friend, I was actually able to learn how to change the size of quilt-block patterns and before I knew it, I was competently working with proportions and percentages of all types! The hardest part was getting past my belief that I couldn’t do quilt math because it involved numbers. Here’s how it works. All you need is an inexpensive calculator, a little bit of courage, and the phrase:
“Ya start with whatcha want, and ya divide it by whatcha got.”
Imagine a darling little appliqué that’s just perfect for your wall, but the 12″ block is too large. You decide you’d like to make it 10″ square. You take the 12″ pattern to a photocopier with the intent to make it smaller, but what percentage should you make it? In the words of my friend, “Ya start with whatcha want, and ya divide it by whatcha got.”
Begin with your goal—it’s the reason you have to deal with quilt math in the first place. What you want is a 10″ block, so punch “10” into your calculator first. Hit the division key, then enter the number “ya got,” which is 12. Press the “=” key. The number 0.83333333333 pops up.
The copy machine wants a percentage, so move that pesky decimal point to the right by two spots, and then you’re done. Because this is a quilt, not a suspension bridge, you don’t need all of the decimal points, so ignore them. You need to reduce the 12″ pattern to 83.3% to make a 10″ block. Yes, it’s that easy to figure out.
Let’s work it the other way and make it a little more complex. You have an appliqué pattern for a 6″ x 7 1/2″ heart, and you decide you’d like to make it at least 8″ wide, but you’re clueless how tall that will be. Ask yourself, what is it you want? An 8″-wide block. What do you have? A 6″-wide block. 8 ÷ 6 = 1.3333. This is what I call the “proportion number.” Move the decimal point two places to the right, and you’ve successfully determined you need to enlarge the heart pattern 133.3%. How tall will it be? In this case you multiply the original height (7 1/2″) by the proportion number, which is 1.3333. So, 7.5 x 1.333 = 9.99975. The heart will be about 10″ tall.
One way to check that you did the math correctly is to remember the following. The proportion number will always be greater than 1.000 if you’re enlarging something, and will always be less than 0.999 if you want to make something smaller. Always. If you want to reduce a pattern but you have a proportion number larger than 1.000, you likely entered the wrong number into the calculator first. I do it all the time.
Remember, “Ya start with whatcha want.”
When changing the sizes of blocks, always do the proportion calculations with the numbers for finished sizes, not cut sizes. This is because you use different numbers to add seam allowances to a triangle (7/8″ for half-square triangles or 1.25″ for quarter-square triangles) than you add do for the seam allowances of a square or rectangle (1/2″). Do all the proportion calculations for the finished pieces first, and then add the seam allowances.
I hope you were able to face all this number stuff without getting a headache, though I’m certain those of you who find math easy are rolling your eyes by now. Did you find this information helpful? Would you like more posts on quilter’s math, or would you like to read about something else? Let me know in the comments. And remember, to keep quilts in proportion, start with what you want, and divide it by what you’ve got.
Find more how-to quilt resources—all free and downloadable!—on our How to Quilt page.
Very helpful information! I love easy math or tricky math made simple. I am in quilting because I enjoyed geometry so much in school. The fact that I did so poorly in Algebra has not held me back but I might have a few more quilts done by now if I had had "the math knack"
—Michelle Harrison on June 8, 2012Just got some great ideas and tips. First time here, but liking it alot.
—Judi Cabanaw on June 8, 2012I can do this! Thanks.
—Judy Maggio on June 8, 2012I am a fairly new quilter and I really loved this tutorial. It has made something I thought difficult to be very easy. Please do more.
—Madeline Watson on June 8, 2012You make it sound so simple out of something that has baffled me.
—Pat Moseman on June 8, 2012Thanks for clearing this up.
I would LOVE to have more math information. In particular, I would really appreciate knowing how you take a pattern for a quilt that is large and make it smaller. I can’t quilt something that is queen size but so many patterns are in queen size or larger. How do you make the adjustments???????
—Claire Desrochers on June 8, 2012Brilliant!
—Kari on June 8, 2012Is there a place I could go to to copy this information without having to write it all down by hand? Your method was very helpful. Thanks, Daisy
—Daisy Christopherson on June 8, 2012Great tip! Thanks for the easy solution!
—Sandra Thiesen on June 8, 2012Now this was wonderful! I’m going to print it out and keep in my "book of notes" for future use as I do like to change sizes…but didn’t know how to do that. Thank You!
—Jane Knoll-Tenney on June 8, 2012"Ya start with whatcha want…" is very beneficial and I printed it to keep with my quilting reference books. I learned something new today–thanks sew much!
—Tam on June 8, 2012This is absolutely brilliant! Thank you for sharing.
—Alberta on June 8, 2012Thank you for usable, understandable information! I am among the math inept group…this was clear, concise, and simple. I can do this! Please do more.
—Pat K on June 8, 2012That made so much sense. I think I can remember "you start with what you’ve got."
—LeAnne L on June 8, 2012I’m with you on the math part. Luckily, my husband was a math teacher so I go to him with all that stuff and he figures it out "right quick" for me.
However, I’m going to make a note of what you said above because sometime he may not be around when I want to get something done "right now"!
—Marvelyn Adams on June 8, 2012I love this math tutorial. Everything that helps to make quilting easier is great! You presented the information in a very easy to follow manner. Thank you.
—Lynn on June 8, 2012THAT is wonderful information … I am copying it and spreading the good word .. along with a link to here – really appreciate your aking that time to share this.
—Sandie McFerran on June 8, 2012Thank you so much for this easy method to get what I want.
—Geri on June 8, 2012I do alot in my head and come out quite close but sometimes
it takes a few trial and errors, now I will not have to waste
my time and get right down to quilting. thanks again
I love your post!
I, for one, would love to see more articles like this. I especially liked the fact that you focused on one concept, explained it in an easy to understand fashion, then gave simple examples for practical application.
—Stephanie on June 8, 2012“You need to reduce the 12″ pattern by 83.3% to make a 10″ block.”
Did you mean to use ‘ to’ instead of ‘by’ in that sentence?
If a block is reduced ‘by’ 50 % it finishes at a quarter of its original size so 80+% would be an even smaller block.
Sorry to be pernickety, but I used to teach this sort of thing….
—Gloria B on June 8, 2012That was incredibly helpful. I am going to print it out and keep a couple and give some to friends.
—Denise Cabral on June 8, 2012Thank you very much!
Great information presented in an easy to remember way. Look forward to more of the same. Thanks
—Gina Burgess on June 8, 2012Good Job. As a former math teacher, it was nice to see an easy way for others to understand. A friend of mine who is a math teacher posted it. Well explained for math-phobic people.
—Kathy Elliott on June 8, 2012Please do be persnickety, Gloria! That was my copyediting goof, and I appreciate your comment. The post has been corrected.
—Tina on June 8, 2012Excellent post! Although numbers and math don’t intimidate me, this post explained the process to enlarge and decrease a pattern very clearly. I would definitely like to read more posts like this.
—Signe on June 8, 2012Thank you very much for this article. Frequently I would like to make something a different size than the original pattern. Your article makes it more enjoyable – and easier – to do.
—Marie on June 8, 2012Thank you so much for making a very difficult task so easy. I am going to share your tip with my mini-group and other quitting buddies.
—Victoria W on June 8, 2012Daisy, if you have a printer you can print the blog post. Or you could copy the post and paste it into a document. Hope that helps!
—Tina on June 8, 2012I am a math person & I still found this helpful. What a good way to tell my friends, because what I was saying wasn’t helpful. Yes, please more math. Thank you!
—Sharon on June 8, 2012I like this kind of information. I can remember that phrase, so it will help me. Yes, more posts like this. Thanks.
—Joanna on June 8, 2012Thank you for this math lesson. It is going to be so handy to keep nearby.
—Donna Hendricks on June 8, 2012This helps a lot. I loved the humor in it as well as the information.
—Patty M on June 8, 2012Thank you. Your article helped out a lot. It is rather funny to think something so easy always sounds so difficult.
—Margie on June 8, 2012Brilliant…i can’t tell you how many times i struggle with this..you are my aha moment ..thank you tons
—mdm samm on June 8, 2012This was a wonderful teaching lesson. Thanks for making it so simple.
—Rae on June 8, 2012Great tutorial…will come in very handy! Thanks so much and, yes, please do more!!!
—Terry on June 8, 2012I love the math lesson and would love to share it with my guild.
—Charlene S on June 8, 2012Thanks for a great article! You sparked some fun ideas! And I’m terrible with math, so this is a huge help.
—Lisa Mayfield on June 8, 2012Thanks for the math – you made it easy!! I would like to hear more quilting math.
—Ruth B on June 8, 2012The link seems to bring you to this post for the scrape- book. The math does bring problems when you want to make quilt patterns for different size block. Thanks for the info on how to resize.
—Linda C on June 8, 2012I’m usually not afraid of math calculations but this makes it SO easy and fast. Thank you for making it so straight forward.
—Liz Dicrescenzo on June 8, 2012I’m good with math, but not without a formula. I always confuse myself whenever I try to figure out how to re-figure the size of something.
Thank you for providing a nice catch phrase for remembering the formula!
“Ya start with whatcha want, and ya divide it by whatcha got.”
Ya gotta love it!
Please keep these types of posts coming. Too many people "assume" that quilters come with the prepackaged knowledge.
Please! When I first started quilting I had to research what "quilt in the ditch" meant because I was too embarrassed to ask. Everyone acted like it was common knowledge!
—Crazy Cuban on June 8, 2012Thank you. So helpful
—Naomi on June 8, 2012Robin, this article is priceless! Printing and saving it today. More please.
—Joan, Australia on June 8, 2012Very helpful. I’m printing it to put in my tips and patterns notebook for future reference! Thank you!
—Jan Maybee on June 8, 2012This is the best blog post I’ve read in a long time. I’m printing this out for my sewing room. Thanks!
—Ginger on June 8, 2012Great article. You’re phrase is catchy, which makes it easy to remember for those that have difficulty in how to resize something. I think you should post more articles like this. I’m a math whiz, but I always try to find ways to simplify math for those that struggle with math. This is a good one!
—Lynnita on June 8, 2012The proportional maths tutorial is the most succinct I’ve read. I love maths and geometry, but I would have taken twice the number of words to explain what you did – and believe me, some friends have had to put up with that. I would love to see more lessons of that caliber. I will point some friends in your directions, I’m sure they’ll get more quilts done. Many Thanks.
—Cherie Hoyle on June 8, 2012Thanks for the simple explanation. Imagine if they taught math in school by way of crafts. Maybe more girls would go into STEM careers because they’d get over their fear of math.
—Jusa on June 8, 2012Hi Robin, this is my second attempt to submit my comment. Such easy to understand grass roots instructions, I’m printing them today! More please.
—Joan, Australia on June 8, 2012Finally an explanation I can understand! Your simplified way of re-sizing block was very helpful.
—Marjorie on June 8, 2012I would love more of these helpful posts.
I would enjoy any topic.
Thank you for writing this article. Math and I are not good buddies. I have printed this simple to understand method and will use it with pride. Keep writing about quilting math for the mathematically challenged like me!
—Onita Oles on June 8, 2012This is absolutely outstanding. I happen to good with figuring stuff out but this is an amazing trick. I’m sure I will be using it often and YES I would like more "Stitch This" things like this one! Great job!
—Helen Cheney on June 8, 2012I did enjoy this article and you made it very easy to understand. Yes, I’d like more math! I’d like more explicite details when changing a pieced block and figuring out exactly what size to cut, etc.
—LJ on June 9, 2012That was really a great way of teaching that simple method! Yes Yes Yes, more Quilt math would be super! Thanks so much!
—Duane Wiley on June 9, 2012Excelente la informacion,de mucha utilidad,Dios bendiga a todos los que generosamente comparten ,muchisimas gracias !!!
—marita on June 9, 2012I love this column. I will use this info for sure. I also have a problem regarding changing the block size to what I want but not being able to change the sashing to the appropriate proportion. I remember Jinny Beyer using some sort of formula that said: "this is to this as that is to that" but I can’t for the life of me remember how you did it.
—Kathleen King on June 9, 2012Do you have an easy solution for that one? Thanks.
This type of information is really helpful…even if you can do the..this doesn’t tax my brain as much. I for one would like to see more of this type of information. Thanks so much!
—Cindy on June 9, 2012These are some great ideas! I look forward to discovering more ideas along the way. Thanks!
—Donna on June 9, 2012This type of information is really helpful…even if you can do the math…this doesn’t tax my brain as much. I for one would like to see more of this type of information. Thanks so much!
—Cindy on June 9, 2012Please, more posts on quilter’s math. They are very helpful; and the older I get, the more help I need!
—Elizabeth P. on June 9, 2012I really appreciate the math lesson. Could you address the topic of borders and how to keep them proportional to the size of the blocks in the quilt or to the pieced unit?
—Shirley on June 9, 2012I really appreciated this information. I have a project that has been waiting for me to figure out the size of the fill in blocks for some pre-made squares. Thank you so much!
—Patty Moffitt on June 9, 2012Obrigada, ajudou muito
—Maria Nogueira on June 10, 2012Genius!! I can figure this out now too!!! Can’t way to "show off" with this information!! I will be pinning this on my Quilt and Sew board on Pinterest for future reference!! Thanks!
—Michele T on June 10, 2012Thanks for your quilt math post. I would be able to figure it out by myself, but only after sitting and scratching my head, and pulling out pencil and paper and trying to remember my high school algebra. You really made it straightforward!
—Barb Johnson on June 10, 2012Love the math….part of why I like quilting so much…a perfect combination of creativity and numbers. You’ve made it very practical and memorable. Thank you!!
—Lorraine on June 10, 2012If you press the % (percent) key instead of the = (equal) key on the calculator, you will get the percent for the copier, without having to move any decimal points.
—Debbie R in ABQ on June 10, 2012I too am math challenged, but found this easy to understand. I like to do miniature and small wall hangings so this will make it easy to shrink a pattern. I’m going to print it out and keep it handy. I’m the newsletter editor for my quilt guild. Can I have permission to put your article in our newsletter? We have all level of quilters in our guild and am sure they would love this tip. Thank you!!
—Kim Smith on June 10, 2012more quilter’s math…..please. Thank you – you are kind. Any info pertaining to quilting is appreciated. Taking the mystery out of color selection would be great too.
—Linda on June 10, 2012Hi Maria, we’ve translated your comment to read: "Thanks, helped a lot." Thank you for your comment!
—Jenny on June 11, 2012Hi Marita, we’ve translated your comment to read: "Excellent information, very helpful, God bless all those who generously share, many thanks!" Thank your for your comment!
—Jenny on June 11, 2012Thanks so much for taking the time to simplify a haunting task. I can do this and I will print this info. to place in my notebook of treasured quilt tutorials.
—Mdee on June 11, 2012Love the "start with" math thingy! Awesome. And, thanks!
—Barbi Brunson on June 11, 2012I will be sure to share this with new quilters I meet as it is so memorable. Thank you, and yes, more math tutorials are always welcome, as are other tutorials.
—Theresa on June 11, 2012Thank you so much for making it simple! I too was mathematically challenged – esp in Trigonometry but this actually makes sense! I laughed out loud when I read the "Suspension Bridge – NOT" comment. That keeps things in perspective, somehow and doesn’t interfere one bit with my quilting enjoyment. I am a competent beginner and just beginning to try my own ways of doing things so I love this kind of challenge – using the old traditional blocks and resizing and reworking them.
—Shairon on June 12, 2012Thanks for the info, very helpful.
—Sydney on June 12, 2012Great lesson- and i Loved your way with words!
—NOLA on June 12, 2012Thank you. Your tip is simple and very helpful.
—Bernice on June 12, 2012Kathleen and Shirley (and others)
—Robin at Martingale on June 12, 2012Once you figure out your "proportion number" you can use it to calculate the new sizes for borders and sashing. If you size a 10″ block to 12″ the proportion number is 1.2″ (12″ divided by 10″ = 1.2). Multiply any of the pattern’s finished measurements by 1.2 and you will know the finished measurement for your realized piece. For example, if the quilt originally had 4″ borders, multiply 4″ x 1.2 = 4.8″. I’d make it easy on myself and plan on 4 3/4″ finished borders. This works for making quilts smaller too. Size a 12″ block to 9″ and the proportion number is 0.75 (9″ divided by 12″ = 0.75). Multiply any of the original finished pieces by 0.75 and you will have the proportion for the smaller quilt. An original 1.5″ sashing would be 1.13″, or close to 1 1/8″. Thanks!
I just opened a small quilt shop and I am always trying to find info for my customers to make things easy. One of my customers sent me to your link and am I happy.. You made it so easy! I also struggle with math and finding quick answers for customers. This tip is so great I will be passing it on to so many that will be just thrilled. Please continue with all the math help you can. Thanks soooo much. Sharyn and many of my customers
—Sharyn Meredith on June 13, 2012This was so helpful!! ….and written so even I could understand it!! I would LOVE to see more quilting math!! Math is NOT something that I do well!
—Lynn on June 13, 2012Thank you for this much needed information. I’ve printed it so I can share it with my Bee. I am so bad at numbers I couldn’t begin to explain sll that you’ve taught us here. If I infringed on a copyright let me know. I will not sell my printed copy.
—Donna on June 13, 2012Thank you so munch! I love the lesson and very helpful for a project I wanted to enlarge.
—Sonia Webers on June 13, 2012Thank you so much for this information! I will be printing three copies – one for the bulletin board in my sewing room, the second for the bulletin board in my classroom (I teach junior high English but sometimes help my students in other subjects), and the third to pass on to the math teachers at school. Your explanation "Ya start with want ya want" makes it so easy.
—Anne Johnson on June 13, 2012Great information. My quilting friends think I am a math whiz but you make it so much easier.
—Denise C on June 15, 2012I enjoyed the help with math to enlarge or reduce a pattern. I was good in math during school, but that was a lonnnnnnnnggggggg time ago.
thanks so much.
—Susan A on June 15, 2012Oh my! You made that so easy! Thank you from the bottom of my heart. Really! Just wonderful. So happy I found Stitch This! I read every single one that pops in my inbox. THANK YOU
—Polly Hada on June 15, 2012This info is so helpful…and will save my husband lots of grief. Thanks so much. Would love more math tutorials.
—Kathie on June 16, 2012Thank you. This will be saved in my helpful hints file. The way in which it was presented was very easy to understand. Please continue with the quilt math lessons.
—Cheryl Kochick on June 17, 2012Excellent information. Even as a bookkeeper I find math perplexing and hard to remember. Now I have this in my file for quick reference. Thanks!!
—Sue Desrochers on July 14, 2012Thank you for the wonderful sizing of a pattern info. Explained enough that my non mathmatical brain got it!
—Jewell on July 16, 2012Thank you for the information. The way that you have put it seems easier to remember. I have put the information down so I do not loose it!! Thank you once again!
—Tammy Hempel on February 26, 2013Great info, was looking for this as I need to make a 10″ block into a 12″ block. Thank You!
—Sue on Feb. 26 2013 on February 26, 2013