Disappearing Nine-Patch (with sizing table)

The disappearing nine-patch is my new favorite block. It’s so simple to make, but looks like you pieced together a ton of small squares and rectangles. Great effect with minimal effort—my kind of thing.

Take these, for example. Just some basic nine-patches—all the same.

Then, they are cut into quarters.

And sewn back together into a four-patch.

To become all of these!

See? Simple-looks-complicated. Lovely.

Math

If you don’t want to do the calculations, here’s a table of sizes:

Starting square sizes and corresponding disappearing nine-patch block sizes
Starting Square	Finished Block
Common precut sizes are bolded
1″	1″
1.5″	2.5″
2″	4″
2.5″	5.5″
3″	7″
3.5″	8.5″
4″	10″
4.5″	11.5″
5″	13″
5.5″	14.5″
6″	16″
6.5″	17.5″
10″	28″

Unfortunately, some common block sizes, like 6″, 8″, and 12″, end up requiring the starting squares be cut to third-inches, so I didn’t include them above. You could try rounding up to the nearest eighth, and use a generous ¼″ seam for the nine-patch piecing (and back to an exact seam for the four patch)—if you’re adventurous and aren’t concerned about absolutely perfect points.

Otherwise, the math isn’t that hard for these once you know how to do it.

To calculate final size from your starting squares

Example using 3″ squares.

Short answer: (Square Size × 3) − 2″
Example: 3″ times 3 equals 9″; 9″ minus 2″ equals 7″. 3″ squares make a 7″ disappearing nine-patch block.

Long answer:

Add together a row of squares. Example: 3″ times 3 pieces (a row) equals 9″
Subtract the row seams (½″ per seam, two seams). Example: 9″ minus 1″ equals 8″
Subtract the four-patch disappearing seams (½″ per seam, one seam). Example: 8″ minus .5″ equals 7.5″
Subtract your final piecing seams for the finished size. Example: 7.5″ minus .5″ equals 7″ finished block

To calculate starting squares from finished block size

Example needing 5.5″ finished block.

Short answer: (Finished Size + 2″) ÷ 3
Example: 5.5″ plus 2″ equals 7.5″; 7.5″ divided by 3 equals 2.5″. 2.5″ squares make a 5.5″ disappearing nine-patch block.

Long answer:

Add your piecing seams to the finished size. Example: 5.5″ plus .5″ equals 6″ unfinished block
Add your four-patch seams (½″ per seam, one seam). Example: 6″ plus .5″ equals 6.5″
Add your nine-patch seams (½″ per seam, two seams). Example: 6.5″ plus 1″ equals 7.5″
Divide by 3 to get your individual square size. Example: 7.5″ divided by 3 equals 2.5″ starting squares

Have fun with your own disappearing nine-patches! Let me know what you make, I’d love to see it.

15 Responses to “Disappearing Nine-Patch (with sizing table)”

Michelle

1:00 am | 08/16/12

Thank you for a great tutorial. I was looking for the calculations and you have explained them very well.
Jan

12:46 pm | 12/07/14

Thanks for this. Great instructions.
Cheryl

2:15 pm | 01/31/15

Thank you for your help ! Now I have to figure out a finished 12 1/2 block !!! help
Misty

6:33 pm | 06/30/15

If I start with a 3.5 inch square, I always end up with a 9 inch block. What am I doing wrong?
- raevenfea
  
  7:53 pm | 07/11/15
  
  If all of your seam allowances are a proper 1/4″, your unfinished block should measure 9″. Then, when you piece them together, you’ll end up with a finished 8.5″ block. Sounds like it’s coming out correctly.
Ronnie chapman

8:26 am | 02/22/17

Many thanks for your excellent tuition. even I can understand that. Have quilted before but never did that block. Back after 10 year spell of illness x
Zenia Rene

7:14 pm | 04/06/17

Yes…thank you for doing my quilty math. It is NOT my favorite thing!
Diane

6:40 pm | 08/10/17

Thank you for the math calculations, my blocks have turned out great!
Antoinette

5:31 am | 10/29/17

Great tutorial for a beginner. Thank you so much!
Maggie Smith

10:16 am | 01/08/18

Brilliant! Just what I was looking for!
Colleen

4:38 pm | 08/30/18

I. Not great with math. I have 4 inch squares and 5 inch squares. How many do i need for king size quilt
- raevenfea
  
  5:56 pm | 09/04/18
  
  Hi Colleen, that depends on a lot of factors, mostly the finished size (not all king size quilts are the same measurements). If you google “How many blocks do I need for a king size quilt”, there are a lot of resources to help you figure it out.
Revital

2:33 pm | 09/02/18

Hi, I started with 6” blocks. When do I square the blocks, the original 9 patch or after cutting into 4? Thanks
- raevenfea
  
  5:55 pm | 09/04/18
  
  It’s up to you, Revital. I tend to square up before cutting into 4 (I think it’s less work that way), but either way will work.
Susan

12:54 am | 10/30/18

Thank you for your table and formula. In your table, how do you define finished block? Does it mean finished, as in pieced into a quilt, or does finished mean it will still have 1/4″ deducted all around the block for seaming into a quilt?