Easy Triangle Quilting Patterns
You can create an endless number of unique quilt designs using half-square triangles. Half-square triangles, also known as isosceles right triangles, tessellate perfectly and can be arranged to create stars, flowers, pinwheels, stripes, diamonds, diagonals, animal shapes, and much more. It's possible to sew a quilt using nothing but equal sized half-square triangles, which means you can cut your triangular patches in bulk to save time.
Below are galleries of patterns using half-square triangles to give you some idea of the types of quilt designs that are possible. From the basic quilting blocks you can devise even more intricate patterns. The best way to create your own quilt patterns is to print sheets of blank square grid paper, divide the boxes into triangles according to design you have in mind, then shade the triangles with colored pencils or markers.
In a half-square triangle quilt pattern, every triangle is matched with another to form a square block. There are two ways that two square blocks can be placed adjacent to each other, labeled as Arrangements A and B in the diagram on the right.
Most quilt patterns use a mixture of these two arrangements, which gives rise to the practically infinite number of different triangular designs you can quilt. However, there is one pattern that exclusively uses Arrangement A, and one pattern that exclusively uses Arrangement B, shown in the diagrams below.
Easy Cutting Tool For Triangular Quilt Patches
A rotary cutting tool like a pizza cutter is the best way to cut hundreds of identical shapes precisely so that the edges match up perfectly. The Fiskars rotary cutting set lets you cut multiple layers of fabric at once without the fabric slipping, so you'll always end up with a perfect stack of identical patches to make your picture-perfect quilt. The board has grid lines and a 45° angle line to help you cut half-square triangles accurately.
Some Galleries of Half-Square Triangle Quilt Patterns
Here are diagrams of triangular arrangements used to create various motifs and traditional quilting patterns. Some quilting pattern blocks have traditional names, often more than one. For a list of names, see this resource or this resource.
A fun way to create your own quilting blocks besides drawing them on grid paper is to use tangrams. Solving tangram puzzles uses the same part of your brain as quilting, and can inspire you to devise new blocks and patterns you never thought possible with mere triangles and squares.
Some Tessellating Quilt Block PatternsClick thumbnail to view full-size
Above are ten tessellating quilt patterns that require only squares and half-square triangles. Tessellating cats make a quirky and fun patchwork project, ideal for children's bedding or unique hand-made gifts. Tessellating cats and tessellating squirrels can be embellished with buttons and embroidery to bring out the details of the face and body. For fun, you can combine the tessellating cats, fish, and squirrels in the same blanket. The tiling flower pattern is ideal for adult bedding or sofa covers.
8-Pointed Stars and Octagons
With squares and half-square triangles you can create 8-pointed star and flower patterns and octagonal motifs. When designing star quilt blocks, it's important to know that the ratio of a square's diagonal to its side is sqrt(2):1, or approximately 1.414 to 1.
Some Quilting Math
When piecing together triangles to make an 8-pointed star block, you should pick lengths so that the straight vertical and horizontal lengths are approximately equal to the diagonal lengths. This can be achieved using the 3&2, 4&3, and 7&5 ratios shown in the diagram below. When the straight sides have lengths 3, 4 and 7, the diagonal lengths are approximately 2.828, 4.243, and 7.071, which allows you to make stars with almost perfect 8-way symmetry.
The reason why these length pairs produce an aesthetically pleasing effect for eight-pointed stars is because 3/2, 4/3, and 7/5 are increasing better and better approximations of the square root of 2. The square root of 2 is approximately 1.4142 and it is important in quilting math because it is the length of the diagonal of a square whose sides have length equal to 1. You can use this square root of 2 aspect ratio calculator to find larger number pairs (such as 11&8, 17&12, or 23&16) that give a ratio close to the square root of 2.
Number of Triangles Needed
If the quilted area inside the border is L inches long by W inches wide, and you are only using half-square triangles that are T inches long on the sides (not diagonal), then the number of triangles you need is given by the formula
Number = (2*W*L) / T^2
For example, if the quilted area is to be 80 inches long by 60 inches wide, and the triangles are 5 inches along the sides, then you compute
Number = (2*60*80) / 25
so you need to cut 384 triangles to complete the quilt.
Seam Allowance for Isosceles Right Triangle Quilt Patches
For isosceles right triangle patches, if you want to have a 1/4-inch seam allowance then you need to cut the triangles so they are larger than the finished triangle by 7/8 inches. For example, if the size of the half-square triangles is 4 inches (measured along the short sides) when they are sewn into the quilt, then the size of the raw fabric pieces must be 4 7/8 inches.