|
Fabri-Calc for Quilters
With this convenient little tool, you won't need to do all of the calculations shown below. Just enter the size of your blocks, the size of your quilt, the number of triangles, and the calculator does the rest. |
Note that if you are cutting strips in order to make squares, no matter what size square you are cutting, add 1/2 inch to the finished size of your square, and 3/4 inch for half square triangles. For example, strips to make 3 inch finished size square patches will be cut 3 1/2 inches wide. Strips for half square triangles will be cut 3 7/8 inches wide.
To make squares, you will cut 3 1/2 inch pieces from the 3 1/2 inch strips, making 3 1/2 inch squares.
It will take 3 3/4 inches to make 2 half square triangles from a strip 3 7/8 inches wide.
The following is an example, using the quilt design shown below. The quilt block is pictured below. The number marked in each patch is the number of the color as it is referenced in the calculations below.
|
|
Assumptions for this quilt:
These calculations are for a quilt that has 9” blocks.
Each patch is 3” square, finished size
The quilt has 4 blocks across and 6 blocks down for a total of 24 blocks
Step 1
The first step is to determine how many of each shape can be cut from a strip of fabric.
To do this, I assume that my fabric is 40” wide. Although I know that much of the 100% cotton fabric is available in widths of 42” to 44” and sometimes even 48” wide, I like to be conservative in estimating the width. I would rather have fabric left over than to run out of fabric in the middle of the night!
The following chart shows how to make that calculation:
|
shape |
width of fabric |
|
size of patch for the shape |
result (# of strips) |
actual # of shapes per strip* |
|
Squares |
40 |
divided by |
3 1/2 (3.5) |
11.4 |
11 |
|
HST** |
40 |
divided by |
3 7/8 (3.875) |
10.3 |
10 |
*Assume you will get fewer of the shape from the strip than the calculation shows, and round down.
**HST = Half Square Triangle
Step 2
The second step is to calculate the total number of patches of each shape required to make your quilt. First, take a look at the block and count the number of squares of each color, and then the number of half square triangles of each color and write them down.
Then multiply your counts by the number of blocks in your quilt.
These calculations are shown in the chart below:
|
|
shape |
# in each block* |
|
# of blocks |
total # required patches |
|
Color 1 |
Squares |
2 |
X |
24 |
48 |
|
|
HST** |
4 |
X |
24 |
96 |
|
|
|
|
|
|
|
|
Color 2 |
Squares |
2 |
X |
24 |
48 |
|
|
HST** |
2 |
X |
24 |
48 |
|
|
|
|
|
|
|
|
Color 3 |
Squares |
1 |
X |
24 |
24 |
|
|
|
|
|
|
|
|
Color 4 |
HST** |
2 |
X |
24 |
48 |
* Count the number of each shape and color in one block.
**HST = Half Square Triangle
Step 3
Now you are ready to calculate how much fabric of each color you need using numbers from the calculations in the previous two charts.
Color 1 
|
shape |
(A) |
Divide (A) by (B) |
(B) |
(D) |
(E) |
(F) |
(G) |
(H) |
(I) |
|
Square |
48 |
divided by |
11 |
4.3 |
5 |
times |
3.5 |
17.5 inches |
1/2 |
|
|
|
|
|
|
|
|
|
|
|
|
HST |
96 |
divided by |
20 |
4.8 |
5 |
times |
3.875 |
19.4 inches |
5/8 |
|
|
|
|
|
|
|
|
|
|
|
|
Total |
|
|
|
|
|
|
|
|
*** 1-1/4 |
*This time, round up so you will have enough fabric
**To calculate the width of the strips you need to cut, add 1/2” to the finished size of your squares, and 7/8” to the finished size of your Half Square Triangles
***Rounding up – I would buy 1 1/2 yards of Color 1
Color 2 
|
shape |
(A) |
Divide (A) by (B) |
(B) |
(D) |
(E) |
(F) |
(G) |
(H) |
(I) |
|
Square |
48 |
divided by |
11 |
4.3 |
5 |
times |
3.5 |
17.5 inches |
1/2 |
|
|
|
|
|
|
|
|
|
|
|
|
HST* |
48 |
divided by |
20 |
2.4 |
3 |
times |
3.875 |
11.7 inches |
3/8** |
|
|
|
|
|
|
|
|
|
|
|
|
Total |
|
|
|
|
|
|
|
|
7/8*** |
* Half Square Triangle
** This actually comes out to 1/3, but the math is easier if it is rounded to eighths
***Rounding up – I would get 1 yard of Color 2
Color 3 
|
shape |
(A) |
Divide (A) by (B) |
(B) |
(D) |
(E) |
(F) |
(G) |
(H) |
(I) |
|
Square |
24 |
divided by |
11 |
2.18 |
3 |
times |
3.5 |
10.5 inches |
3/8 |
|
|
|
|
|
|
|
|
|
|
|
|
Total |
|
|
|
|
|
|
|
|
3/8*** |
***Rounding up – I would get 1/2 yard of Color 3
Color 4 
|
shape |
(A) |
Divide (A) by (B) |
(B) |
(D) |
(E) |
(F) |
(G) |
(H) |
(I) |
|
HST |
48 |
divided by |
20 |
2.4 |
3 |
times |
3.875 |
11.625 inches |
3/8 |
|
|
|
|
|
|
|
|
|
|
|
|
Total |
|
|
|
|
|
|
|
|
3/8*** |
***Rounding up – I would get 1/2 yard of Color 4
Remember, this is just for the blocks in your quilt. If you are planning to use the same fabric for the borders, buy more.
If you are really organized and know how your borders will look, you can purchase what is required to make those borders.
Since I prefer to wait until I have my quilt blocks together before I plan my borders, I generally buy an extra yard of each fabric I plan to use for the border.
In summary,
|
|
1 1/2 yards Color 2 1 yard
Color 3 1/2 yard
Color 4 1/2 yard
Happy Quilting!
Penny Halgren
Penny is a quilter of more than 27 years who seeks to interest new
quilters and provide them with the resources necessary to create
beautiful quilts.
Inspiration and Education for Beginning Quilters
www.Rag-Quilt-Instructions.com
Fast, Fun and Funky Quilts
www.Fabric-Postcards.com
Quilt Greetings Across the Miles
This article courtesy of http://www.How-to-Quilt.com.
You may freely reprint this article on your website or in your newsletter
provided this courtesy notice and the author name and URL remain
intact.
©2006, Penny Halgren
|
The Machine Quilting Adventure Batting can make a difference in your machine quilting. Discover how to choose batting for your quilt that will show off your machine quilting AND be easy to work with. Click here to learn more |
